Re: Kindle Fire
Its hard in general terms to mention anything but in broad strokes about Android, as every manufacturer uses their own build and some perform better than others.
Those that got it right (from my personal experience) are Samsung (Galaxy tab), HTC (on the Flyer), Sony and maybe (although I've only used a prototype version that wasn't the full spec).
They all make good use of the hardware (even the Flyer that is a lower spec than the rest), actual feel tends to be pretty good.
I personally didn't find the general controls (those found at the bottom left of the display) particularly intuitive and found I'd keep pressing the wrong one (bringing up a menu instead by going backwards, etc.), the look and feel does differ so I can't really make any statements beyond that, I didn't find the layout offensive, maybe a little busy, but on most of them you can customize pretty heavily so its not too much of a worry.
Integration tends towards being simple and easy, with some of them having settings for most major brand computers/mobiles/etc being a few clicks to set up.