Apple's tagline for the iPhone 6S is 'the only thing that's changed is everything', highlighting that the brand knows this is a phone that looks an awful lot like 2014's model.
It makes sense that Apple would try its hardest to show that, despite the handset looking identical to the iPhone 6, there have been loads of changes under the hood that make this an attractive phone in its own right.
The chassis is stronger, the camera sharper – with a new Harry Potter-esque way of capturing your snaps – and there's even a completely new way of interacting with the screen. On paper, it's an impressive upgrade.
But when it looks identical to the iPhone 6, people will be desperate to know if the iPhone 6S is enough of an upgrade to justify the price. While the upgrades seem great, is it worth going all the way up to the iPhone 6S, or would the 6 do?
In terms of raw price, we're in a weird situation now. Samsung and the rest of the Android crew have been slowly ratcheting up the price of their high-end phones to the point where they're actually eclipsing the iPhone 6S at launch.
While Apple put its phone into a market where the Galaxy S6 was significantly cheaper there are new boys on the block in the form of the Galaxy S7, LG G5 and HTC 10. Either way, the iPhone 6S has a lot to live up to.
In the UK you'll likely have to part with between £50 and £100 upfront to get the phone for £36-£38 per month (if you want a decent slug of data and minutes) with the 6S starting at £539 (US$649, AU$1,079) for the 16GB model, £619 (US$749, AU$1,229) for the 64GB model and £699 (US$849, AU$1,379) for 128GB.
It starts at $649 if you're looking to pick it up off contract in the US, with the new $32.45 monthly cost if you're thinking of getting locked into Apple's yearly upgrade plan.
In reality though, the question of who this phone is aimed at isn't that hard to answer: for most people stuck on the iPhone 5S it's clearly the upgrade they're considering, although the recent arrival of the iPhone SE will surely tempt some of those users who want to stick with the smaller form factor.
Beyond that there's the disgruntled Android owner who's tired of looking at the slicker app experience Apple offers and seeing their own handset looking sketchy in comparison.
(Of course, there are a few people that tried Windows Phones as experiments, but they'd probably be happy with just about any other phone if they're still using a Nokia Lumia 930).
The issue Apple is trying to solve with the iPhone 6S (and the 6S Plus) is how it can convince users, especially in a market saturated with really rather brilliant smartphones, that the 'S' variant of the impressive iPhone 6 is a worthy phone to upgrade to in its own right.
When something is so visually similar, the onus is on the brand to show that the upgrades are really worth the extra cash.
The iPhone 7 is just months away too, so unless you must have the very latest iPhone right now you might want to hold out just a bit longer. Why? The iPhone 7 is set to bring an updated design, more power and an improved camera. And if that doesn't float your boat the 6S will drop in price too, so it's win win!
The iPhone 6S is almost identical to the 6 in every way when it comes to the chassis. There are some very subtle differences, such as a slightly thicker frame and a little more heft, but it's so slight that I kept getting the two mixed up when doing side by side comparisons.
All cases fit both phones just fine too so, apart from a small S logo on the back of the phone, nobody is going to notice you've got the latest iPhone.
But there will be lots of you upgrading from the iPhone 5S, and in that case you'll need to be ready for a really big design change. The metallic chassis feels really nice in the hand, with a ceramic-like feeling on the outside (although if it's anything like the 6 then this can scuff over time if you keep it in a pocket with keys, so you'll need to think about the kind of case you'll want to keep it safe).
If you're not ready to take the leap to the new, bigger form factor, Apple has the new iPhone SE to satisfy your 4-inch cravings.
One of the things that Apple is touting is the fact the iPhone 6S is made of 7000 series aluminum, which is the strongest thing it's ever used in iPhone construction. The obvious connection people will make is with 'Bendgate', when some users claimed their new phone had developed a slight curve in their pocket without much pressure.
The common belief was that these phones began to twist when placed in a rear pocket and sat upon. While it was proven that other metal phones actually were worse when it came to bending Apple didn't come out of the controversy well.
So it's no surprise that, while the company won't admit the real reason, the new iPhone is strong and never going to bend with such pressure. However, I feel like that we shouldn't feel happy our phones no longer bend – this seems like one of the minimum expectations I'd have of a smartphone, not a compelling reason to buy it.
The front of the phone is now covered in a new level of strength, with a glass that's far less prone to shattering when dropped on the floor – now that's something I can get behind. We've not drop tested it - we'll leave that to some other, braver reviewer - if the screen is stronger the responsiveness hasn't dropped.
In the hand, the iPhone 6S still feels like a dream. Even with the extra 14g over the iPhone it feels lightweight, easy to manipulate and really warrants the price. Samsung's new Galaxy S7 Edge invokes the same kind of feeling, and with it you don't mind spending the extra money over a more budget phone.
In terms of design, if you've seen the iPhone 6 then you've seen the 6S. The volume buttons, the power key, the silencer switch and the speaker are all in the same place as its predecessor, with the grille at the bottom very easy to cover when you're watching videos or playing games in landscape.
If you're using the 5S, this is leagues ahead. The construction is good, the materials solid and there's no wiggle in the buttons at all. While you probably never bent your 5S, the idea that the iPhone 6S is stronger will probably please you, however unnecessary the claim is.
Apple's not done anything great with the design of the iPhone 6S, but the iPhone 6 was such a well-created phone that using the same chassis isn't going to harm its chances of success.
However, combined with the higher price and the continued presence of the iPhone 6, I wish we were at least seeing some retooling of the phone to make it seem more attractive.
The screen on the iPhone 6S seems to be identical to the iPhone 6's: we're talking a 4.7-inch affair with 750p resolution, which keeps it firmly in the 'Retina' range that the firm debuted all the way back with the iPhone 4.
It's hard to rate the display, as while it fails on resolution (quite spectacularly actually - phones a seventh the cost of the iPhone 6S offer 1080p screens, Samsung's cheaper phone has four times the resolution of the 6S and Sony has, inexplicably, launched a 4K phone) it doesn't drop too badly on performance.
The iPhone 6S display is clear, bright, laminated to the glass and insanely colorful. The first time I saw it on the iPhone 6 I thought it was a fake picture stuck on top of a dummy unit, such was the clarity on offer.
So to use the same thing on the iPhone 6S makes sense - after all, the lower pixel count means it can be thinner and the battery can last longer, thanks to having fewer pixels to drive.
But there are some things missing: for instance, the contrast ratio (the difference between the brightest and darkest parts of the screen) is still poor, with the black areas looking a little grey. Samsung's Galaxy range predominantly uses OLED technology, which offers 'true' blacks and high brightness and packs a much better visual punch, and would have suited the iPhone down to the ground.
The sharpness in side by side tests is clearly lower too - the 326 pixels per inch is very low even compared the 401ppi of the iPhone 6S Plus - and most other models are over 500ppi to bring really, really clear displays.
Given OLED technology is used in the Apple Watch - and admittedly it looks brilliant - it's a shame the same thing couldn't have been done with the iPhone 6S.
It's important not to get too hung up on screen resolution in a phone - after all, if it's not serving a purpose (hey, Sony?) then it's just wasting battery. But the industry has moved on, and the higher pixel densities on offer are starting to really bring something to the table, with apps and general use looking pin sharp.
Here's hoping the iPhone 7 makes a massive jump forward to join the rest of the pack.
3D Touch, Live Photos and A9 chip
Apple's been hard at work integrating the Force Touch technology from its Watch and new MacBook Pro into the iPhone 6S, but has decided that it needed to give it a new name: 3D Touch.
In terms of all the changes offered by the new iPhone, this is definitely the one you should pay most attention to. Not just because it's the most multi-faceted, but also because it's the only change that I feel confident in stating will alter the way we use our iPhones forever.
The premise sounds simple: the screen now has a third dimension, allowing you to poke 'into' the display rather than just swiping all over it. Apple's likened it to the integration of multi-touch, which ushered in pinch to zoom for navigating through the web and photos... and that definitely changed the way we use smartphones.
While the amount of things you can do with it now is slightly limited, there's no doubt that the ability to poke the screen is going to become a natural gesture over the next few years, especially as app developers get hold of the option.
It's only native Apple apps that have made use of the option for now, and while most of them have some form of 3D Touch-ability, I found myself using it most in messages and Safari.
Let's say you get a message with a link in - asking you to check out a website or asking if you want tickets to 'this' gig. You can just push the link and a little window pops up, previewing the web page and giving you the info you want.
If that satisfies you, then you can just let go of the screen and return to the message. If you need to know a little more then pushing the screen harder will open up the page in Safari so you can explore further.
These actions are nauseatingly called 'Peek' and 'Pop' - but just think of them as a preview and then a harder press actually opens the app and you'll get what I mean.
The same thing for nearly every link in the phone, and the action became second nature within a few days. In fact, it became embedded to such an extent that I nearly broke the screen on a Samsung Galaxy S6 Edge trying to open a link, and got annoyed when I had to actually click a hyperlink in Gmail's web client.
3D Touch is probably the most functional in Mail, where you can preview messages then swipe up, down, left and right to do things like call up menus, archive the message or mark it as unread.
In Apple's presentation this was the headline action of the service, but I didn't find it that useful... like many things I didn't feel like the previous method (opening the email, seeing if I cared, deciding I didn't and then possibly marking it as unread) was a problem.
If anything 3D Touch made me more lazy with my mails... and if you've seen my inbox that's not a good thing.
The big issue I had with 3D Touch was that the previews were static - I couldn't scroll up to see a little more when often I wanted to just get a little more info before deciding if I wanted to open the app. This sounds like a really picky way of describing the action, but given it's meant to be all about convenience I really missed it.
I also found, especially when previewing things like photos, that my finger was right in the middle of the screen and covered a lot of the display - thus making the preview irrelevant.
But that takes away from the excellent idea that Apple's come up with here. Sure, it's nothing more than a super-charged long press, and if anything it's highlighted that Apple should have added in such an action ages ago, given it's been in Android for aeons.
This is definitely the next level though. I've already played a racing game where acceleration and braking were now able to be subtle thanks to the pressure applied, and while it was rudimentary there was definitely a feeling of a more premium 'controller'.
But I've not used the technology much in the last month, if I'm honest. The only thing I've regularly used it for is previewing web links and viewing Live Photos - and the latter because that's the only way to see them, where a long press on non-iPhone 6S models works the same way.
I still think it will be revolutionary, but only when apps start using it. Instagram lets me preview pics this way, but who cares? Just tap and open them. I rarely use the shortcuts on the homescreen, but then again I keep forgetting I can, which is an issue of training users Apple has to overcome.
It will get a functionality boost when iOS 10 lands however, with the operating system update bringing more options and features to 3D Touch, allowing you to do more with the pressure sensing tech.
This will make the iPhone 6S even more powerful, plus it'll also drop in price with the arrival of the iPhone 7 - so it's worth keeping an eye on.
There's greater control over your cursor when typing too, with the inclusion of iOS 9 on the iPhone 6S allowing you to use 3D Touch for precision placement. Hold down on the keyboard and the characters will fade away, leaving you with a track pad to expertly line up the blinking vertical line.
It brings a new level precision to editing text, something which has been a little hit and miss on previous iPhone and iOS incarnations.
While I'll cover this in greater depth in the camera section, it's worth talking about the new function in the new iPhone 6S. While the camera has been upgraded to 12MP, it will now grab a chunk of video before and after the snap (1.5 seconds to be exact) and turn that into a little video.
With audio captured the idea is that the moment is added into the photo, and with a prod from 3D Touch you'll be able to see the story behind the photo. This isn't a new idea, as HTC, Nokia and Samsung have all tried to do it in the past (with limited success).
Nokia and HTC were probably the biggest proponents of the platform, the former using it to do great things like remove people from the photo or providing more editing effects - and HTC even spliced the video into a photos highlights reel to make memories of events like a night out.
Both of these ideas worked well, were genuinely useful and had a strong result - and yet couldn't entice users in (although HTC's now-standalone Zoe app is still being used by many). Apple's method is much simpler, almost hidden behind the photo, where the only proof that there's a dynamic picture in your snap is a little flick of movement as you swipe through the gallery.
However, it doesn't seem like something that will be a big draw - simply because the only thing people want to do is take a photo with a camera and have it come out looking crisp, in focus and full of color. They don't want gimmicks around it, they just want the phone to help them be brilliant photographers.
In fairness to Apple, the Live Photo happens quietly in the background (with only a little 'Live' box at the top of the camera viewfinder telling you what's happening) and doesn't compromise shooting speed or photo quality, and in terms of space it's less than two photographs.
If Apple had changed the 16GB model to 32GB, then perhaps this wouldn't even be questioned, but many people run out of space on their smaller iPhone capacity and doubling the amount of photos taken is going to make things even worse.
As usual, Apple has upgraded the engine in the middle of the iPhone, bringing the 6S into 2015 with it fastest chipset yet. The A9 has myriad upgrades, with things like the M9 coprocessor enabling the phone to record even more motion without impacting on the battery life.
As usual it's been hard to test this out before the official launch of the iPhone 6S, simply because there aren't apps unveiled that can make use of it. The games shown off at the official iPhone debut, like the Warhammer 40,000: Freeblade game, showed that the new iPhone is capable of some truly breathtaking apps and is able to combine them with 3D Touch to enable new methods of gameplay.
But in general day to day use, there doesn't seem to be a lot of difference. Browsing through apps is a snappy as ever (albeit with a very slight delay if you've got animations enabled) and I can't fault the speeds over Wi-Fi or cellular connection.
That's just in day to day use - if you stress test this a little more, you'll see that the iPhone 6S will shave off a few seconds each day through constantly opening and closing apps (see the video in the iOS 9 section to get what I mean).
What was notably absent from the unveiling event was the claims of longer battery life, which you'd have assumed the improved CPU would have offered. However, it seems Apple has decided to use that improved power to deliver 3D Touch and more powerful graphics, rather than extending the battery life of the iPhone 6S.
Give iOS 9 was also supposed to be a bit better on the battery, this is surprising, but I couldn't see any evidence of improved battery management.
Like in recent years, the new iPhone is the poster child for the new version of Apple's operating system - and iOS 9 works really nicely on the iPhone 6S (admittedly, it does so on other models too).
It sounds stupid, but one of my favorite things about the new platform is in the notifications bar - a simple drop down will display the 'Today' section, which contains info about what's going on in the next 24 hours. Here you'll now see the information on anything connected wirelessly - your iPhone's battery life, that of an Apple Watch and even Bluetooth headphones.
Given I'd often see the battery life shown by a tiny little icon in the corner when I connected up a pair of wireless earbuds, this is a big jump forward. It's tiny, but hey, sometimes those are the best bits.
I'm a bit less bothered by the new information screen accessed by swiping all the way to the left of the home screen - which is your favourite people and some internet news.
Here you've got the ability to start a search within the phone or on the web, tap into apps that are most relevant to you at that point, or talk to the people that your iPhone thinks you'll want to talk to.
Come September, the iPhone 6S will get a free upgrade to iOS 10, bringing with it a host of new features including greater 3D Touch functionality, rich lockscreen notifications, enhancements to Siri and a whole lot more.
The news section is what irks me the most. If you're not in the US you won't have Apple's News app yet - so clicking these links will open up Safari. I'm not into politics, but that's all the app wants to serve me.
Download the News app (by changing your region to the US) and clicking these links will take you into the app itself. However, they still don't populate with the topics you're interested in, and all that happens is you're reading it in a slightly nicer manner in the app.
Apple's News app is massively underwhelming. I've used Blinkfeed, Flipboard and Pocket aggregators before, all of which try and suggest news you'd like, and most of them do a better job than this. Football gets confused between the American variant and soccer, the mix of news can default to just one 'channel' (which you can choose to subscribe to) and at startup the app will force you to choose a news site you like, even if you don't like anything on offer.
It's early days for the app, but it's currently getting very close to joining Stocks in the 'meh' folder.
For the rest of the platform, it's hard to decide how to review the current iteration of iOS 9 on the iPhone 6S as it's both radically different and very much the same - which sounds ridiculous but is the only way to describe it.
The familiarity comes from the way it's all set out - Apple's not changed anything in the way you use the phone, meaning you've still got the same rows of apps on the home screens and the Settings menu is still the place to get all your information for what apps are up to.
And that latter point is something that's hugely annoying - Apple's been slowly integrating elements from Android over the last few years, but the ability to change apps inside the actual program is something that's evaded it so far.
This means that if you're having a problem with Facebook and it's sucking down too much battery, you can't do anything about it in the app, rather having to jump out to another app to make the tweak.
Perhaps that's not the best example though - after all, Facebook's app is a complete mess when it comes to trying to alter anything within the app itself - but if you're in the camera and decide you want to film in the new 4K resolution, or alter the quality of the slo-mo video, then you can't do it in the camera app.
It's a trip down to Settings and through the Camera and Photos section (for some reason clumped together) before you can make this tweak.
OK, you can argue that Apple's being consistent in this approach, but it doesn't encourage the user to play with certain new features, and that's a failing in my eyes.
But that aside, I still really like the simplicity and subtle tweaks that Apple's added into iOS over the years, and iOS 9 is by far the best version of it yet. The new font is nice, Siri's abilities are excellent and being able to say 'Hey Siri' from anywhere is a nice move.
I'm not sure how much this impacts the battery life, but it's one of the things that gets turned off when you enter Low Power Mode, so it must have some effect.
The performance of the iPhone 6S is strong - in our Geekbench 3 tests, it ran to an impressive 4417 score, which puts it slightly above the iPhone 6S Plus and within striking range of the Samsung Galaxy S6.
While that's a huge uptick over the iPhone 6's performance, we're at the point where such boosts are becoming redundant. It's helpful, but I can't honestly say the iPhone 6 had a real problem.
But how does that compare in real world usage? We tested the iPhone 6 next to the iPhone 6S (although the former was still running iOS 8) and the new version managed to complete our test 12 seconds faster - the caching and speed with which apps loaded was insane.
Check out the video above to see what I mean, but you'll definitely feel less annoyed with apps taking a few seconds to load with the iPhone 6S.
Siri is now a really functional part of the phone, with both the accuracy and results impressing time and again. Being able to type in a sports team to find out their results and news is cool - for instance, key in the name of your favorite football team and you'll not only get their recent score but also web content that's related, such as video and news.
The ability to work out what you're talking about, making voice searches contextual, is really cool too - being able to see all your selfies in one go is nice to do, although not the nicest thing to see.
Similarly being able to ask to see snaps from a certain holiday is neat (although you'll have to say 'show me pictures from San Francisco in 2013' rather than 'show me pictures from my holiday last year'.)
The camera app on the iPhone 6S is very similar to previous years, with a few small tweaks to add in new features.
The first is Live Photos, which takes a 1.5 second picture before and after the snap and turns it into a small video you can play to capture the memory. Apple's clearly realised that you can only do so much to enhance the camera in terms of image quality and started to work out how to capture more of the moment you're after.
It's hardly a new idea though - although the integration here is impressive and is less onerous than trying to use the Zoe mode on the HTC One series, for instance. The speed with which you can take a photo hasn't diminished either, so you can take multiple pictures in quick succession and the iPhone's A9 processor can work out what needs to be saved to create the Live Photo.
Viewing them is simple too - when in the gallery just prod the screen harder to activate 3D Touch and the memory will come to life. Apple's demo showed beautiful images of waterfalls and children smiling, and it seemed the option seemed to really capture the warmth of the situation.
In reality, the results are a mixed bag. If you're not bracing the camera perfectly against something, or using a tripod, then the video will often start off rather choppy and seem a bit low quality.
The same is true in low light - the frame rate seems to drop a lot in these situations as the phone perhaps is processing the images harder.
Live Photos is meant to be there as an enhancement to your photos, rather than a dedicated moment that you're capturing, which is why it's excellent that it runs so silently in the background. In fact, only a slight movement in the picture in the gallery hinting that there's anything to check out.
But in reality too many of them will seem a bit too erratic and choppy to be something you'd want to show off - this is a nice idea, but like Nokia and HTC before it, Apple's not really nailed this feature. Having the audio is great though - it really adds to the image.
Here's our look at the iPhone 6S camera in action:
And I'll be fair - I've been using this phone for a month and I've enjoyed Live Photos far more than I thought I would. 90% of what I took is boring when viewed as a Live Photo - it's just vague movement of people posing, and the software update to get rid of the bit where you put the phone down can't come soon enough - but there were a few genuinely great moments.
The first was at a surprise foam party. It's hard to convey the beauty of being covered with foam by a grumpy-looking man in the corner, but a picture doesn't do it justice. Showing our exploits to others was a series of wet-looking people as pictures, but poking the screen showed foam flying everywhere and the music we were all dancing to.
Again, there was the weird speeding up of the footage and a really choppy look to things, but the magic of the night was brilliantly captured.
The option to toggle Live Photos on and off is good though - it's only a tap in the bottom corner of the phone, and the feature can still work with HDR mode activated too.
The camera itself is fine - with a bump to 12MP, the sensor can capture more than ever before, letting you zoom in a little more and get more refinement in your snaps.
Apple doesn't seem to have upgraded the camera much here beyond bumping the megapixel number though - the launch focused on the fact that the pixels are more adept than ever at focusing quickly and eliminating cross talk, and that's fine.
It's just the 8MP iSight sensor on the iPhone 6 took really great photos too, and focused quickly, and didn't have a huge amount of crosstalk.
A cynic might suggest that Apple's only bumped the number up to compete with Samsung and Sony, who are getting great snaps from 16MP and 23MP sensors - but that would take away from the great quality of pictures on offer here.
In practice I really couldn't see a great deal of difference between the iPhone 6 and the 6S in terms of picture quality. There were some differences, obviously, and that was mostly seen when zooming in on the pictures - but the brightness levels or colour reproduction seemed pretty similar.
In extreme testing, there are improvements to be found, as with almost minimal light, the new iPhone is more adept. That's all the more impressive given the higher amount of pixels, which usually leads to poorer lower light performance.
The iPhone 6S comes with a 5MP camera to help improve those pictures that can only be taken from the front of the phone and the rear 12MP iSight camera simply won't do.
The front facing camera is imbued with all the same features as the rear sensor, and that means it even includes a flash.
Before you spit out your smoothie / tea / soy latte in amazement at the thought of an iPhone having a front flash though, don't get too excited. It's not an LED light taking up precious space from the front of the phone, but Apple's way of using the screen more effectively.
The LG G3 had a special mode to illuminate selfies, but that just shoved the viewfinder into a smaller image on the screen and lit up the edges, which provided an erratic glow.
The iPhone 6S has a smarter mode: it'll take a quick look at the surroundings by brightening the screen then amp up the brightness by three times to provide said flash. What's impressive is that the phone works out the colour balance of your surrounding and then provides the right level of white to get the best picture.
It's awesome to have all the same options - HDR mode, filters, timer and flash - all available in the front-facing and rear-facing camera - and the quality of the photos is improved as a result, with the 5MP sensor providing a real enhancement over the paltry 1.2MP sensor used in previous models.
We've pitted the iPhone 6S camera against the snappers on some of the key competition; the Samsung Galaxy S7, HTC 10, LG G5, Huawei P9 and Sony Xperia Z5.
During our test we snapped a variety of different shots so see how each phone performed. The iPhone 6S was consistent with its ease of use and it didn't take any bad pictures. That said, it didn't exactly shine either, falling into the middle of the pack overall.
The battery life in the iPhone 6 was finally not terrible and while the iPhone 6S hasn't really pushed that ability on any further, it's still in the mix with the top smartphones on the market.
That doesn't mean it has stellar battery life by any stretch though, as it will still struggle to last the day. It's only saved by the fact that most of the other top phones - the HTC 10, Huawei P9 and LG G5 - all can't manage the same thing either, the handsets all desperately trying to fire more pixels in the screen or update more apps to provide a richer experience.
What is cool is that Apple now provides more info as to what's going on behind the scenes with the battery. Not only does it tell you what's been nabbing all your power in the last 24 hours / week, but it will also tell you how much of that was background and foreground effort.
That means if you see Facebook is taking most of your battery and constantly updating when you're not looking, you can disable it to get back that life (and not really lose much functionality).
Or perhaps it's an app that's acting up - if so, delete it and reinstall and you'll probably find it behaves itself much better the next time around. You understand that apps you're looking at all day long drain the battery - anything on the screen is a power hog - but when you can finally get a handle on what's doing it tin the background you can really begin to manage your battery better.
That doesn't mean I was able to really get a lot of battery life out of the iPhone though. Even when I'd managed to get rid of the apps that were taking the most power, things like Apple Music would pop up and take their space, despite not being in the foreground.
The battery life issue doesn't seem to be based on anything in particular - if you're listening to a lot of music on Spotify or keeping things updating in the background then it'll eat the power without you really noticing, leading to around 30% when it's time to go home.
Keeping the screen brightness down will help a little here - but if Apple could make an OLED screen work on the iPhone then it would take back even more battery life.
The reason could have been shown off at the Apple launch itself: the iPhone 6S was seen in a video sporting 1715mAh battery, which is much lower than the 1810mAh offering placed in the iPhone 6 - that additional 3D Touch circuitry certainly seems to have come at a price.
In terms of out and out testing, we ran a Full HD at full brightness for 90 minutes from full power. The iPhone 6S dropped down to 70% power left, which isn't a great score. It's even worse when you consider that the iPhone 6 managed to get to only 74% in the same test - like for like, the older model is capable of running longer.
That patchy battery performance was also highlighted in our flagship battery test, where we put the iPhone 6S up against the Samsung Galaxy S7, HTC 10, LG G5, Huawei P9 and Sony Xperia Z5 to see which performed the best.
The simple test saw a web script run on each phone, loading a series of different websites on a continuous loop at full brightness for two hours. Unfortunately for the iPhone 6S it was the poorest performer - so if you're planning on doing a lot of web browsing you might want to take it a little easy on this phone.
Finally, iOS 9 offers the chance for you to extend your iPhone battery life further by simply tagging an option in the settings.
The move will disable certain aspects like the phone constantly listening out for you saying 'Hey Siri', or keeping your mail updated in the background.
In fact, if you're not bothered about the phone constantly listening for your 'Hey Siri' voice command, I couldn't really see a problem with using Low Power Mode all the time - apart from the fact the battery colour moves from green to yellow to signify that the phone is in the lower effort mode.
There's no option to toggle it on and off in the Control Centre at the bottom of the screen, which means you'll need to head into the settings to disable it. However, when your phone reaches around 80% charge the iPhone will automatically offer to turn it off for you, as it's decided that it's got enough power to see it through whatever you're going to be doing next.
It's a real shame that the iPhone 6S' battery life isn't a little bit better - it's making me wonder how much that 3D Touch system is impacting on the power management. If it's a lot, then you'll have to hope that the improvement in the interface as developers get on board is worth it.
Movies and music
The iPhone is still one of the better devices out there for watching films on, but mostly because the integration with the iTunes store is so strong.
While Google Play is getting to a similar level, there's something about the ease with which one can download a whole array of films or fill in missing TV series that makes me drawn to Apple's option when it comes to getting the latest movies.
And watching them on the iPhone 6S is pretty darn good too, thanks to the aforementioned laminated glass. The resolution might not be top notch on the screen, but the overall quality when watching downloaded or streamed content (either from the iTunes Store, Netflix or even YouTube) is really something to behold.
Thanks to the lightweight chassis that Apple's hell-bent on adding into every device it makes, the experience of holding the iPhone 6S for an extended period isn't a horrid one. The screen feels a touch small, but that's just all about perception.
There was a time not that long ago where a 4.7-inch display would have been the perfect size for watching movies on, but now we've been spoilt by both tablets and the larger-screened phablets, and the 750p resolution on something of this size just feels a little too dinky for slurping down too many series in a row.
However, it's a great trade off when it comes to getting a phone that you can toss in a pocket and not think about sticking out the end, so unless you're desperate to improve your commute with the entire James Bond series (which I would doff my cap to you for) then this phone will probably suit you just fine.
It's interesting that the 3D Touch system hasn't been integrated into the movie watching experience - on the MacBook you can use Force Touch (which is pretty much the same thing, but likely with fewer sensors) to decide the level of scrubbing speed depending on the pressure you apply.
It's not a big deal, but it's something that would have been nice to see on the new iPhone.
Music - well, Apple Music
The audio capabilities of the iPhone 6S are, once again, really rather brilliant - and as loathe as I am to admit it, really augmented by Apple Music. I only say loathe because I'm getting tired with the amount of streaming services available at the moment, not because it's a poor service.
I'm yet to be convinced by Beats 1 as a radio station (I've got loads I'm already into based on specific genres, rather than the pick 'n' mix attitude of Zane Lowe and chums) but the range and catalogue on offer is strong from Apple. The curated playlists perhaps aren't in the same league as Spotify, but it's when you use Siri to get you some tunes that things really start to pick up.
Saying 'Siri, I want to hear the latest EDM tunes ' will result in the voice-powered asisstant popping off to the Apple Music app for you and starting something playing instantly (although in this case, it gave me the Spiderman 2 theme).
It's great for when you're out running and want to change the genre, or fancy a certain song suddenly, and takes away the horrible choice of having to stop and look at your phone or carry on and try to do it on the fly.
In terms of the actual music player itself, well, Apple Music has made it a little confusing. Yes, your own MP3s are stored there just fine, but they're tucked away in the corner, with things like Artists you can follow being shoved down your throat beforehand.
I feel almost guilty for disliking that - there's part of me that can't help but buy into any service that plays on how cool liking music is, and as someone who's really, really into Girls Aloud and Basshunter, I've never really felt like part of the crew. I wonder if following artst will make things feel a little bit cooler, that I might start getting into Motown or Jazz from 1950s... but there's something about terrible dance pop that keeps drawing me back in.
At least Apple still caters for me.
I can't see myself stepping too far from my Spotify subscription though when the Apple Music trial ends - with so many playlists and the excellent Discover Weekly on the go, I prefer to get my music from there, and the quality through a decent pair of headphones on the iPhone is superb.
Speaking of headphones, there's a new feature of iOS that I'm really into: when you connect a pair of wired or wireless headphones, the lock screen will show you your favourite music app so you can get the most out of your music.
What's impressive is how intelligent this service is - working out that Bluetooth headphones mean running and thus I want Spotify, while wired options will generally see me listening to my favourite podcasts.
That's the kind of smarts I want to see from my phones, and it's good to see Apple matching Google Now in terms of helping you save a few taps on your phone's screen.
As per usual, the iPhone has launched into a saturated market when it comes to top end smartphones. This year it's the return to form of Samsung, the same low-cost offering from LG and an impressive option from Sony, all costing the same or less as this new iPhone 6S. So is it worth more than the competition?
Samsung Galaxy S7
The Samsung Galaxy S7 hasn't been crowned our best phone in the world for nothing. It's got a larger, higher resolution display, superior camera and even more power packed under the hood.
Its Android Marshmallow OS and TouchWiz overlay may not be as simple and clean as iOS, but it offers a wealth of additional features and controls - plus the always on screen is a handy addition.
Battery life also exceeds the iPhone 6S, with the Galaxy S7 comfortably seeing out a full day on a single charge, and taking heavy lifting tasks in its stride.
The iPhone 6S and Samsung Galaxy S7 are around the same price, so the choice is are you looking for the best of Apple, or the best of Android? If you don't care about OS, the S7 is the greater device, but for iPhone stalwarts it probably doesn't do enough to draw you away from Apple's grasp.
While Apple and Samsung may have played it safe with their latest flagship offerings, LG isn't backwards at coming forwards with new interpretations of the mobile phone.
It gave us buttons on the back with the G3, a leather-clad phone in the G4 and now the G5 boasts modular capabilities.
As well as a large QHD screen with always-on display, plenty of power and dual-cameras on the rear, the G5's real party piece comes to light when you pull its bottom off.
Swap out the bezel piece with the Cam Plus or Hi-Fi Plus modules and you've instantly added extra functionality to the phone. The modules are a little half baked, and the battery life needs improving, but if you're looking for something a bit different from your flagship phone the G5 offers it up.
The iPhone 6S is great, but what if you fancy something a little bit bigger? No more are you forced off the Apple ecosystem, as the Cupertino firm now has its own Plus size models.
As the name suggests, the iPhone 6S Plus shares many similarities to its smaller brother, but the main point of different is the screen. Here you get a full HD resolution stretched over 5.5 inches - perfect for gaming and movie watching.
The larger dimensions will put some off - and quite right too, this is a beast in the hand - but compare it to similar sized Android devices and apart from the bulky bezels at the top and bottom it shapes up rather nicely.
It's still premium, the interface is still clean, there's a decent slug of power and with a bigger battery crammed inside it'll last a bit longer too.
You're looking for the power of the iPhone 6S, you're not fussed about the 3D Touch interface and you're thinking that it's all just a bit too big for you.
Well, Apple's decided that the iPhone SE is the solution you need - it's an identical chassis to the iPhone 5S meaning the handset is really palm-friendly and the 4-inch screen a dream to glide your thumb around. The same powerful A9 chip and 12MP camera are on board too - this really is a bundle of power in a smaller phone.
It's also cheaper too, so if you want all the next-gen features without the added heft, that's when you should be looking at the iPhone SE.
I saw in a recent BuzzFeed interview that Tim Cook bristled at the idea that the iPhone followed a 'tick-tock' release schedule for its phones, and that we're firmly in the 'tock' phase.
He preferred to say that the iPhone 6S is a 'significant change', and the tagline of 'The only thing that's changed is everything' shows that Apple really wants the world to think of the iPhone 6S as powerful phone in its own right.
And it is. This is Apple we're talking about, and it has so many fans that no matter what phone is released from the factory, it'll be considered as many people's next upgrade.
Because, for all the power and style of Android handsets, they've still not matched the subtle, refined feeling you get from using the iPhone, the confidence that the apps will work better than anywhere else, that you'll experience fewer crashes, that everything will function as you expect it to.
That doesn't mean everyone has to like the iPhone, but it's easy to see why the fans need a really big push to leave the ecosystem and jump to Android.
Tim Cook called the iPhone 6S' 3D Touch a game-changer, and I'm inclined to agree. It became second nature to use it after only a couple of weeks' use.
The native apps are already using the system well, and it's quickly becoming a fun game to work out where things allow you get little previews or offer shortcuts without needing to leave the app itself. But when developers get their hands on the power, I can see some really clever apps and games emerging - and that will give a real lead over the Android versions.
The rest of the things I liked are baked into the iPhone itself, and always have been. I appreciate the strong and usable camera, giving great snaps no matter what kind of pics you're trying to take - and the sharpness has been upped this year too.
The overall design of the phone is strong, as it was in the iPhone 6, and I still like the feeling of holding the ceramic back of the 6 or 6S - it just feels great in the palm.
The battery life of the iPhone 6S leaves a lot to be desired - and while I'm a big fan of 3D Touch, I'm not sure that I'm happy with the fact I have to accept lower battery longevity to have the privilege.
If Apple ever launches a smaller phone with the kind of battery life the iPhone 6S Plus offers, then it's going to have a smash hit on its hands, which makes it all the more confusing that the brand hasn't decided to bring something like that out already.
While it's stupid to be disappointed by something so obvious, the fact the iPhone 6S is identical (in design terms) to the 6 still irks.
If only the screen had ben upgraded, or the battery life lengthened through a larger power pack in there, it would be something to cling onto.
But instead we're left with a phone that's hard to explain to users who want to know what's good about the new phone when it looks so similar - there are only so many ways you can talk up 3D Touch.
Apple's idea that 'The only thing that's changed is everything' seems instantly to be a bit of misnomer. Yes, on paper you can point to a lot of things: improved structure, new interface method, Live Photos, a sharper camera, a more powerful engine, but in reality only 3D Touch offers a significant upgrade.
The iPhone 6S is a long way from a bad phone because, simply, it's an iPhone. That's not me saying that anything Apple does it going to be great, but the reason so many people fall over themselves to get the new iPhone is because they know it will be a solid experience with very intelligent interface touches and a great app store, coupled with a great camera. To many, that's all they need.
But being part of the Apple experience comes at a high price - literally. It's still one of, if not the, most expensive flagship phones on the market, and as such needs to impress in every way, which the iPhone 6S doesn't quite do. The iPhone 6 remains on sale at a lower price, and the difference between it and Apple's latest phone is negligible.
If you're desperate to get a new iPhone, and can afford it, I'd recommend the new iPhone 6S wholeheartedly, especially if you're jumping from a 5S. It's got a great interface that's only going to get better, and the overall package is still excellent.
However, if you're a little more thrifty (and still in the Apple camp) then perhaps the iPhone 6 (or iPhone SE) will suit your needs a little more adequately - you're not losing a lot and still getting a great phone.
That said, with the iPhone 7 due to launch in September you may want to hold off to see what Apple has in store. Even if the iPhone 7 isn't too your liking, the iPhone 6S will get a price drop when it successor drops off, which will save you a bit of money.
It's only because the iPhone 6 was so impressive that the iPhone 6S gets four stars - it needed a massive leap forward to eclipse that model, but it's still a great phone in its own right.