It's been a long time since Apple was under this much pressure to impress with a new iPhone. After last year's rather straightforward upgrade, the Cupertino company needed something special, and something to fight back against the moves being made by its rivals.
The iPhone 6 and the iPhone 6 Plus are Apple's counter-punches, but how do they stack up against each other? And which one should you be spending your cash on?
The world's iPhones have got thinner and lighter since 2007 but this year Apple has really worked some iPad Air-style magic on the dimensions of its latest handsets. The 4.7-inch iPhone 6 is just 6.9mm thick (shaving another 10% off the already slim 7.6mm iPhone 5S) while the 5.5-inch iPhone 6 Plus has a thickness of just 7.1mm.
The differences over the 2013 batch of iPhones is noticeable, and Jony Ive's team have rounded the corners of the iPhone 6 and 6 Plus to accentuate the slimness of these devices, as well as adding more premium metal to the mix.
The familiar iPhone button layout has been rejigged to allow for this new super-thin frame. Most significantly, the power button moves from the top to the side, while the bands running across the top and bottom of the devices are introduced to improve reception and connectivity.
These are two almost impossibly svelte handsets, with the iPhone 6 offering a slightly thinner design than its more expensive iPhone 6 Plus sibling. If you're a phablet fan or have particularly large hands, the bigger model is the one you'll have your eyes on. The same gold, silver and grey options are available across the board.
iPhone 6 vs iPhone 6 Plus: Screen
The screen is where we find the biggest gap between the iPhone 6 and the iPhone 6 Plus - it's the main distinction between the models. The iPhone 6's display measures 4.7 inches corner-to-corner at a resolution of 1,334 x 750 pixels (or 326 pixels-per-inch).
The 6 Plus ups this to 5.5 inches and a resolution of 1,920 x 1080 pixels (401ppi). These figures put the iPhone 5S firmly in the shade, with its 1,136 x 640 pixel, 326ppi display.
All that means you get more pixels on the 6 Plus spread across a larger area. Website text will be bigger, movies can be viewed from further away, text will be sharper, and so on. It also makes the device harder to hold in just one hand, but the one-handed mode built into iOS 8 should be able to alleviate some of those problems. The weight of either the iPhone 6 or the iPhone 6 Plus shouldn't be a problem, at least.
One extra benefit you get from the additional screen space on the iPhone 6 Plus is the ability to run apps in landscape mode, iPad-style - it's a bonus for anyone who wants more room to work with on their handset. If you use any serious productivity apps on the go then bear this in mind, though compatibility varies between apps.
A recent update to Netflix's app means that Netflix now supports 1080p video playback on the iPhone 6 Plus' 5.5-inch screen. This means that if you're a regular user of the Netflix app and want the best possible playback quality on an iPhone, then you'll want to go with the iPhone 6 Plus.
iPhone 6 vs iPhone 6 Plus: Camera
Both of the new iPhone models feature the same camera lens technology. That means an 8-megapixel shooter (as with the iPhone 5S) but an improved f/2.2 aperture and processing algorithms, so your pictures are going to look better than ever in all conditions.
Bear in mind that the iPhone 6 will be easier to handle with one hand when framing shots, but the iPhone 6 Plus will give you more viewfinder screen space to get your image lined up correctly.
The iPhone 6 Plus features optical image stabilization (OIS), while the iPhone 6 only has regular image stabilization.
Also built into the iPhone 6 and the iPhone 6 Plus is the NFC technology required for Apple's new mobile payments system, so you can use either phone to make contactless payments when you're out and about. The iPhone 6 is a little more pocket-friendly, which can help if you want to travel light.
The tests measure the exposure and contrast, colour, autofocus, artefacts and noise levels to determine an overall score to award to each phone's camera.
In the tests both the iPhone 6 and iPhone 6 Plus scored 82, the highest ever score for a smartphone camera. The Samsung Galaxy S5 and the Sony Xperia Z3 come joint second with 79 points.
Although both the iPhone 6 and the iPhone 6 Plus score the same, the benchmarks did highlight the various strengths and weaknesses between the two iPhones.
For example the Optical Image Stabilisation feature of the iPhone 6 Plus helps reduce image ghosting on HDR images compared to the iPhone 6, with the OIS feature helping to align the multiple images used in the HDR photos.
However during video recording the iPhone 6 Plus suffered from light video stabilisation artefacts that the iPhone 6 didn't, leading DxO Labs to state that the iPhone 6's camera is slightly better for video and the iPhone 6 Plus' camera better for still images.
Although it is close between the iPhone 6 and iPhone 6 Plus, there are a number of tips and tricks that you can use to further improve the camera quality in both phones.
CPU and RAM, battery and price
iPhone 6 vs iPhone 6 Plus: CPU and RAM
The iPhone 6 and 6 Plus unsurprisingly make the jump to Apple's A8 64-bit dual-core processor, giving it more oomph for your games and video editing. On-board RAM remains constant at 1GB, however, so for most day-to-day tasks you're not going to notice a huge difference in the capabilities of these two phones.
The iPhone 6 and the iPhone 6 Plus match in terms of storage capacities too: for the first time there's a 128GB level to join the 64GB and 16GB options. You can pick any of these three with any handset, though the iPhone 6 Plus is more expensive across the board, so you'll be paying more for the same amount of space in return for a larger device and clearer display.
iPhone 6 vs iPhone 6 Plus: Health
We heard plenty about iOS 8 and HealthKit back at WWDC 2014 in June, and the newest iPhones come with all the sensors and gadgetry required to make the most of these features.
There are no differences between the two devices in terms of the sensors they include - driven by the all-new M8 processor - and the main Health app that they run to keep track of all your vital signs.
Again, the only variation you need to think about is the size: the iPhone 6 is slightly easier to take out on a jog or to the gym, while the phablet-style iPhone 6 Plus is better suited for sitting back on the couch and checking out how well your fitness has improved over the past few weeks.
Both give you full access to Apple's new health platform.
iPhone 6 vs iPhone 6 Plus: Battery
The iPhone 6 Plus's larger frame means more room for a bigger battery. It also has more screen to illuminate.
Apple is telling us that its battery lasts for longer than the standard iPhone 6 - 16 days of talk time as opposed to 10, 24 hours of 3G talk time as opposed to 14, 80 hours of audio playback as opposed to 50, and 14 hours of video playback as opposed to 11. Both phones are upgrades on the iPhone 5S in terms of battery life, but the Plus goes even further.
In our tests we found that during light-to-medium use, which included checking emails, recording video, taking a few photos and a couple of hours of listening to offline tracks in Spotify, the iPhone 6 lasted 13 hours with a battery drop to 33%.
The iPhone 6 Plus lasted from 7am to around midnight after a day of similar use, and there was still battery life left before it was plugged in at night.
In our TechRadar battery test the iPhone 6 lost 26% of its battery when playing a looped 90 minute full HD video. The iPhone 6 Plus did slightly worse in the test, losing 27%, showing that on video it's not the strongest thanks to the extra pixels, although in day to day use it fares better.
iPhone 6 vs iPhone 6 Plus: Price
If you've read all the way through this article, you'll know that the iPhone 6 Plus comes with some premium features - bigger screen, more pixels, landscape mode - and those features come with a premium price too.
It's $100 more than the iPhone 6 at each price point, with the smaller iPhone 6 starting at $199 for the 16GB edition and the larger iPhone 6 Plus starting at $299 for 16GB. If you splash out on the new 128GB version of the Plus, you're looking at the most expensive iPhone yet.
SIM-free in the UK, the iPhone 6 will set you back £539 (16GB), £619 (64GB) or £699 (128GB). For the iPhone 6 Plus you can add on £80 or more - that equates to £619 (16GB), £699 (64GB) and £789 (128GB). Those prices will be lower on any contracts you sign with mobile operators.
For the US, contracted prices are all we have right now. $199 (16GB), $299 (64GB) and $399 (128GB) for the iPhone 6, and exactly $100 more expensive at each point for the iPhone 6 Plus.