I'll throw my opinion in since I've owned a lot of ereaders
-Kindle Fire : nice size, a little heavier (vs regular Kindle) for extended reading. I sold mine because it did not do so well as a back up web browser.
-Kindle Keyboard : Probably my favorite eInk reader. Light efficient no problems...
Ya I bring mine to work and make all my patients hold it to see how light/thin it is ... Apple should send me a free one for all this advertising I'm doing for them :)
Ya I just ordered some $5.00 TPC one, don't care much about looks on the back that I never look at, I just want it covered so it does get scratched up in my man bag ;)