Perhaps in part explaining why Amazon's Fire tablets are no longer Kindle-branded
"This is not to say the HD 10’s screen is unacceptable, merely that it’s not ideal for reading. Thankfully, its bright and colorful display, and low resolution and pixel density don’t have such a negative impact on games, videos, and other visual media. In fact, the tablet’s unusually wide form—it has a 16:10 aspect ratio—makes it well-suited for movies and TV shows. High-definition titles play nearly full-screen, without the thick black letterbox bars you see in tablets with 4:3 aspect ratios.Amazon's Fire HD 10 tablet a rare misfire for company - Fortune
As for performance, despite the inclusion of a quad-core processor, I found the Fire HD 10 to be sluggish. Amazon’s own Washington Post app took 10-15 seconds to load, and I sporadically experienced long load times in Amazon’s Silk Web browser as well. When you tap in a text field, the keyboard often takes several seconds to appear. It’s experiences like this that can make the tablet aggravating to use."