The Asus made Google Nexus 7 is the slightly more compact of the two tablets here measuring 200 x 114 x 8.7mm, compared to the 186 x 128 x 9mm Kindle Fire HDX 7.
It means the Nexus 7 is a touch taller than its Amazon rival, but its more slender frame means it's also lighter with the Wi-Fi only model tipping the scales at 290g and the cellular version registering 299g.
The Kindle Fire HDX 7 isn't particularly heavier at 303g and 311g respectively, but that does translate to a very slight additional heft in the hand.
Asus has kept the same rounded design from the original Nexus 7, but has slimmed down the newer version and applied a soft touch rear which hugs the sides of the tablet.
This makes for a comfortable and grippy service which feels pleasant to the touch, and its lightweight nature means you can easily hold the Nexus 7 in one hand - you can even grab a corner with thumb and forefinger like you would a book.
Bezels down either side of the screen (when in portrait) are relatively slender while there is a significant chunk of vacant space above and below the display.
Turn the Nexus 7 landscape however and that additional space comes in handy as it gives you somewhere to rest your fingers. That's especially useful if you're watching a movie or TV show.
From the rounded design of the Nexus 7 to the angular stylings of the Kindle Fire HDX 7, and immediately it feels chunkier than its Google rival.
The sharp edges and defined slopes on the rear gives the illusion that there's a bigger difference in depth between the two tablets - in reality though the difference is just 0.3mm.
Amazon has opted for a similar soft-touch finish on the rear of the HDX 7, and it too wraps round the sides of the tablet to meet the glass front.
Again this provides a good level of grip and you can just as easily hold the Fire HDX 7 in one hand without your wrist giving way.
The soft touch rubber is broken up by a glossy strip of plastic on the Kindle Fire HDX though, and this houses the dual speaker grills.
It makes the tablet look a little more interesting, but the glossy plastic finish is a magnet for fingerprints and it can end up looking mucky rather quickly.
There are suitable bezels all the way round the screen, which means there's always space to rest a finger, but also makes the Kindle Fire HDX looks rather bulky.
Both tablets feel solid and well built, while button, speaker and microUSB port locations are all well placed for easy manipulation.
As we've already mentioned both tablets sport 7-inch displays, but even though they share the same 1200 x 1920 resolution and 323ppi pixel density they aren't completely identical.
Both Amazon and Asus have opted for a 16:10 aspect ratio on the screens which is better suited to movie playback. Apple's iPad range uses the squarer 4:3 format.
The Kindle Fire HDX uses IPS LCD technology which produces bright, clear images on screen, but the Nexus 7 features LED-backlit IPS LCD tech offering up even brighter and more natural colours.
Whites and blacks are better defined here and this provides a more realistic finish which is especially obvious when it comes to watching movies and TV shows.
You won't be disappointed with the display on the Kindle Fire HDX, as it's still a great offering, but if you find yourself next to someone with a Nexus 7 there may be a touch of jealously coursing through your veins.
That's because Amazon has rebuilt Android Jelly Bean from the ground up, plugging in all its own services while removing applications and features related to Google in its Fire OS 3.0 interface.
For anyone who's already deeply integrated into Amazon's ecosystem, from Kindle and Amazon Prime Instant Video to its own App Store and main retail site, the Fire HDX 7 has all these services available at your fingertips.
Instead of getting a series of customisable homescreens the Kindle Fire HDX sports a carousel of your recently used apps, books, films etc, while applications are listed underneath.
It's certainly a very different approach to Android and one that can take a bit of getting used to if you're already familiar with the operating system and the forced nature of Amazon's services can be frustrating.
For first time user, however, the walled garden nature on the Fire OS interface is less confusing and more intuitive as it puts media front and centre without a confusing array of settings and options.
You also benefit from Mayday, a feature which is unique to the Kindle Fire HDX family. Tap this button and you're put through to an Amazon advisor who can assist you with anything regarding your new tablet.
The service is free and operates 24 hours a day, seven days a week, 365 days a year. You'll be able to see your advisor on screen, but they can't see you and Amazon aims to respond to you're Mayday call within 15 seconds of you hitting the button.
The locked down OS can be a hindrance though, as you don't get access to any of Google's applications, such as Maps, Drive or the Play Store.
Amazon's App Store is reasonably well stocked, but it doesn't give the full range of applications that you find in Google Play and the store's interface leaves a lot to be desired.
At the complete opposite end of the scale is the Nexus 7 which sports an unadulterated version of Android 4.4 KitKat - the latest flavour of the OS to roll off productions line over at Google.
This is Android in its purist form, with not skin or additional features bolted onto the system and for fans of the interface it's pretty much as good as it gets.
The big advantages over the Kindle Fire HDX are the presence of Google's fleet of apps and the Google Play store - giving you access to a much wider range of applications, plus there's greater flexibility allowing you to customise the Nexus 7 to suit your personal needs.
While Google has its apps, music and video services front and centre you're not forced into using them, and you can quite easily visit other provides for your media needs.
The open nature of Android on the Nexus 7 can be a little daunting for the less tech savvy, although Google has made it easier to grasp with each iteration.
Being a Nexus device the Google Nexus 7 will always be among the first to receive any software updates, bringing new features and general improvements to the tablet, meaning it'll be rocking the latest technology on screen.
The Google Nexus 7 comes well equipped in the power department with a 1.5GHz quad-core processor, 2GB of RAM and an Adreno 330 GPU under the hood.
If that sounds impressive the Kindle Fire HDX boasts an even better processor with a 2.2GHz Snapdragon 800 chip running alongside the same amount of RAM and graphical processor as the Nexus.
The additional processing grunt inside the Fire HDX 7 is apparent when running benchmarks, with the Amazon tablet coming out top in our Sunspider and Peacekeeper tests.
In the Sunspider benchmark (lowest score is better) the Nexus 7 averaged a respectable 1148.4, but it was blown out of the water by the Kindle Fire HDX 7 which racked up a score of 718.1.
Things were slightly closer in the Peacekeeper test (higher score is better), but the Kindle Fire HDX won comfortably with an average score of 864 to the Nexus 7's 647.
While the Amazon tablet may have a comfortable lead in the benchmarks, when it comes to general usage there's very little to pick between the tablets.
Applications open promptly, and both can handle multiple apps and graphical intense games without issue.
We did find that the Kindle Fire HDX 7 was a fraction of a second quicker at loading web pages than the Nexus 7 - but the difference is minimal - and the Google Chrome browser on the Nexus 7 is actually easier to use.
In short, both tablets come with plenty of power and should be able to manage pretty much anything you throw at them, although the Kindle Fire has the upper hand looking forward as its processor has more longevity.
Neither tablet in this versus is media shy, with the Amazon Kindle Fire HDX 7 and Google Nexus 7 jam packed with an arsenal of opportunities to satisfy your entertainment needs - be it movies, music or books.
With full HD, 7-inch displays both tablets are great for watching movies on, and their small form factors allow you to hold them for an extended period of time without your wrists giving way.
On the Kindle Fire HDX 7 there's a wide range of HD films and TV shows available for you to buy or rent. Prices are comparable to other services and you can either stream them over Wi-Fi or download them for consumption at a late date.
HD movie rentals tend to range from £2.49 to £4.49, while you'll usually have to fork out between £5 and £15 to buy a film outright.
Amazon also has its own streaming service known as Prime Instant Video (formerly LoveFilm), which requires a monthly subscription of £5.99 per month for unlimited streaming of a range of shows and movies.
The Kindle Fire HDX 7 has one final trick up its sleeve when it comes to video playback and that's X-Ray for movies and TV shows.
X-Ray shows additional information (gleaned from Amazon owned IMDb) on the video you're watching, from the list of stars appearing to the songs playing and facts about the show or film.
The Google Nexus 7 has its own arsenal of movie and TV shows available to rent or buy via the Google Play store.
Pricing is very similar to that of Amazon and there's a huge selection for you to choose from. Google doesn't have its own streaming service, and there's nothing similar to Amazon's X-Ray feature here either.
As we've already mentioned when it comes to view your favourite TV shows and films the screen on the Nexus 7 gives the better viewing experience thanks to brighter and more natural colour reproduction.
Google Play also offers a huge library of music tracks and albums which you can purchase and download, and the search giant even provides some free cloud storage where you can store 20,000 of your tracks in the Play Music app.
Once in the cloud these tracks can be access from most Android devices, including the Nexus 7.
You'll also find that Google has its own music streaming service on the Nexus 7 - and it's something you won't find on the Kindle Fire HDX due to the lack of any Google applications.
Google's All Access music streamer works in a similar way to the likes of Spotify with a £9.99 per month charge for unlimited playback of millions of songs.
Amazon meanwhile also has a decent collection of tracks and albums for you to stream and download, but there's no subscription base streaming service available on the Kindle Fire HDX.
This means you'll have to fork out separately for each track or album, but at least you own it going forward. Amazon's X-Ray feature also presents itself in the music section, providing wider information on the track and artist.
The Amazon Kindle Fire HDX 7 has the upper hand when it comes to books as the retail giant's Kindle service is deeply integrated into the tablet providing an intuitive reading experience.
Battery performance has also been optimised when reading, extending its life allowing you to read for longer.
Google has its own library of books, magazines and newspapers in Google Play, and you can also take advantage of Amazon's Kindle collection by downloading the Kindle app onto the Nexus 7. That's a lot of books to get through.
There's little to choose between the two tablets when it comes to actually reading a novel, with the backlit displays providing very similar experiences.
Storage and battery life
When it comes to storage the Amazon Kindle Fire HDX 7 has the advantage, arriving in 16GB, 32GB and 64GB guises. The Nexus 7 can only be picked up in 16GB and 32GB models, and if you want 4G connectivity you'll have to pick up the latter.
The Kindle Fire HDX meanwhile offers Wi-Fi only and 4G models with all three storage sizes, giving you a wider choice.
It's worth keeping in mind that the quoted storage sizes aren't the amount of available space you'll have at your disposable, as the Android operating system takes up around 4GB of that.
Also consider that neither tablet has a microSD slot to expand your storage options, so a 16GB slate is only worth it if you're going to be using it for emails and surfing the web.
Anyone thinking about downloading a heap of apps, movies and games may want to look to the 32GB and 64GB options to ensure they don't run out of space too quickly.
As is the case with pretty much every tablet on the market these days the batteries inside the Amazon Kindle Fire HDX and Google Nexus 7 are sealed into the units.
This means you won't be able to buy a spare, charge it up and swap it with a flat one if the tablet runs out of juice.
The Nexus 7 houses a 3950mAh battery which Google claims is good for up to nine hours of multimedia usage, meanwhile Amazon reckons its power pack can last up to 11 hours - although it hasn't revealed the battery's capacity.
We found during our tests that both tablets gave pretty strong showings in the battery department, but the Nexus 7 was the better performer.
Each slate was subject to our battery test which sees a 90 minute HD video played at full screen brightness with various accounts syncing the background.
After the 90 minutes were up the Google Nexus 7 had dropped 24% of life, while the Kindle Fire HDX lost 32%.
This means you should be able to get a full days use without having to worry about running out of charge, although if you go on a heavy gaming or movie binge both tablets may struggle to make it to bedtime, especially the HDX 7.
The Kindle Fire HDX can extend its battery life beyond the 11 hour mark if you're predominantly using it to read books, as it has a special power saving mode when it's in reading mode.
Camera and price
The Google Nexus 7 comes out on top in the camera department boasting a front facing 1.2MP snapper and a rear facing 5MP lens, while the Kindle Fire HDX 7 offers just a 1.3MP camera on the front.
Google has recently given its Android camera app an overhaul and the Nexus 7 is one of the first devices to take advantage of the new look app with its oversized shutter button taking up a fifth of the screen.
It's pretty intuitive and with the option to record full HD videos too there is a decent host of features available on the Nexus 7.
Images are passable, but they won't blow you away. Chances are the smartphone in your pocket will be able to take better snaps than the Nexus 7, but for the occasional photo it provides a serviceable option.
Over on the Kindle Fire HDX 7 and the camera app is extremely basic. You get a shutter key, a shortcut to the gallery and a toggle for camera and video modes.
There are no additional features to play with and shots are generally pretty grainy. You won't be taking any pictures to show off to friends and family here.
What the front facing cameras on both tablets do provide though is the possibility for video calls using services such as Google Hangouts and Skype - and for this purpose both are adequately equipped.
In terms of price there's little to separate the tablets. Both start at £199 for the 16GB, Wi-Fi only variants, although Google does charge a little more for the 32GB Nexus 7 which comes in at £239.
The 32GB Kindle Fire HDX 7 is a touch cheaper at £229, but that does include adverts displayed on the lockscreen.
If you don't want Amazon pushing you products every time your lock your Fire HDX then you can select "without special offers", which pushes the 16GB price up to £209, while the 32GB option matches the Nexus 7.
An advantage Amazon has is its 64GB option, but you'll need to part with £259 (with ads) or £269 (without ads).
Wi-Fi only models are perfect if you only really plan on using the tablet at home or at locations with a Wi-Fi network. If you're going to be out and about with your tablet though you'll want to consider a Wi-Fi + 4G LTE option, allowing you to access the internet on the move, just like on your mobile phone.
Amazon comes out on top here, with the Wi-Fi + 4G option available on all three storage models. The 16GB is £269 with ads/£279 without ads, 32GB is £299/£309 and the 64GB Kindle Fire HDX 7 with 4G connectivity is £329/£339.
You're more restricted if you want a 4G enabled Nexus 7 as only the 32GB model comes with the additional connectivity, setting you back £299.
The Nexus 7 does come unlocked, allowing you to pick up a data plan from a network of your choosing, where as the Kindle Fire HDX 7 comes locked to Vodafone.