The Amazon Fire HD 6 is a really good value tablet. And Amazon Fire HD 7 not so much. Here's why.

If you like the size of your Kindle eReader, but want a fully-fledged tablet with a proper web browser, email, Skype and apps, Amazon can now oblige with the Fire HD 6. (See also Nexus 9 review and Tesco Hudl 2 review.)

This isn't simply a Kindle with a colour LCD screen, though. The battery makes it noticeably heavier but it's a bit narrower - and easier to hold in one hand - than the new 7th generation Kindle.

However, it's larger than most smartphones we've seen with 6in screens. This shows just how much bigger it is than the new Galaxy Note 4 which has a 5.7in display - the Fire's bezels seem unnecessarily thick.

If six inches isn't big enough, Amazon also has the new HD 7 which shares the same internal components but has a 7in screen.

Both have the same 1280x800 resolution, and both are good-quality IPS displays. The pair also shares the same front and rear cameras. However, even at £80, the 2-megapixel main camera is poor. At the HD 7's starting price of £119, it's unacceptable.

The front camera is a basic VGA webcam for Skype chats, but selfies are going to be disappointing.

The HD 6 has a single speaker at the bottom on the back, while the HD 7 has stereo speakers which sound better, but it's a shame none of them are facing forward.

A new addition for a Fire tablet is a choice of colours, but we'd advise against the sickly citron colour we've got here. (See also: Best tablets for children.)

Amazon Fire HD 6 and Amazon Fire HD 7 review: hardware and performance

As we've come to expect from Amazon's tablets, there's no expandable storage so you're limited to the 8GB or 16GB of internal storage which Amazon offers for each model. Just bear in mind that the the 8GB version has only 5GB available for apps, photos, videos and other personal files.

Both tablets has a quad-core processor and 1GB of RAM. There's also Wi-Fi and Bluetooth but no GPS receiver, so don't buy a Fire tablet for use as a giant satnav.

Amazon Fire HD 6 and Amazon Fire HD 7 review: Fire OS

The tablets run the latest version of Amazon's Fire OS, which is based on Android. You don't get the Google Play store or any Google apps for that matter, but the Fire OS is easy to use.

It's especially easy to access Amazon's services - which are the reason Fire tablets exist at all - such as Prime Instant Video and Kindle ebooks. You can also buy music, apps, games, magazines, newspapers and audiobooks.

Amazon recently added FreeTime to its tablet range, and this feature makes the HD 6 a particularly good choice for kids. You can create password-protected profiles and different time limits for games and books. The idea is that you can allow unlimited reading but restrict playing time.

This latest version of Fire OS has a new weather app, and the email, contacts and calendar apps have been improved. Email, for example, works much like Mail on an iPhone or iPad.

Notifications now appear on the lock screen, and you can now back up all your data and settings.

On the HD 6, text is sometimes too small to read comfortably, but that's never an issue on the HD 7.

As neither are HDX models, you don't get Amazon's on-device Mayday help service.

More annoying is that there's no ambient light sensor, so brightness doesn't adjust according to how bright or dark it is around you. (See also: The 29 best tablets of 2014 UK.)

Amazon Fire HD 6 and Amazon Fire HD 7 review: Bottom line

It isn't perfect, but the HD 6 is really good value. Performance is well above the level you'd expect at this price, as is the quality of the screen. Some might find the 6in screen too small, though, so it's worth trying to track one down before buying.

It isn't nearly as easy to recommend the HD 7. With both tablets you really need to spend the extra £20 and get 16GB of storage, but that puts the HD 7 in direct competition with 'proper' Android tablets such as the Hudl 2.

This gives you unrestricted access to everything Google, and has a bigger better screen, and is the better choice for most people. SeeThe 10 best budget tablets 2014: Here are the best cheap tablets available to buy in the UK right now.