I received the new Fire HD 8 Plus on the day of its release and I have been using it constantly as my main tablet ever since.
Main benefits: Form factor - the 8 inch is size is perfect for kindle reading and watching streaming services. You can hold it in one hand which is hard to do with a 10 inch tablet. Battery life - Excellent. For kindle reading I can go 3 - 4 days without charging. Battery life goes down with increasing screen bright and streaming. Standby consumes very little battery. USB-C - Infinitely easier to plug it in using a USB- C cable. Less chance of damage compared to Micro-USB socket. Wireless charging - Only found in the HD8 Plus. Makes it so much easier to keep the battery topped up. Sound: I think it's excellent for something so small. There's actually a stereo effect with them! You can easily watch a movie using the speakers alone. RAM: It's 3GB on the HD8 Plus and a no brainer. It'll make your tablet last longer before its next upgrade and less likely to slow down with multiple tabs open on your browser Value for money: It's the best 'branded' tablet you can get for your money without doubt
Ambivalent Screen brightness: it's not bad. Could be brighter. Using adaptive brightness helps battery life but at the expense of a duller screen. Speed: Even with 3GB RAM and a slightly faster processor, it is faster than it's predecessor but nowhere near the smoothness of more expensive tablets but do bear in mind the cost of this tablet. Fire OS: It's locked to the Amazon ecosystem. If you're used to this like I am then it's not a problem at all but if you're expecting a pure Android experience or customising things, looks elsewhere Ads: Mine comes with ads. It means an ad on the lock screen on startup. Not intrusive otherwise.
Downsides: Screen resolution: It it the minimum for the size of the screen. To my eyes it's fine for kindle reading and watching movies but compared to your phone screen which most will be in much higher resolution, things won't be as sharp as you would expect.
Conclusion: Great update. Great value for money. Don't expect miracles. Screen resolution should have been improved.
5 month update: no issues to report. Really happy with this tablet. Battery life and size are the best features. The resolution is not an issue at all when reading kindle and watching HD movies. Downside: would have been perfect if it was a wee bit nippier!