1. touchscreens and eink do not mix. give me fwd/back buttons
2. the newer kindle can only remember your last read place in one pdf. Open another pdf, bam, you're reset back to the beginning on the other! This makes me furious.
3. Windows' pdf reader ups the ante by remembering the place in the last 4 pdfs you were reading. Open a 5th, and the oldest one gets pushed off the bed. You'd think with a 512G machine there'd be enough memory to remember 5, maybe even 6!
4. no MicroSD slot in most of 'em
5. miserable bookshelf display. Come on, how hard can this be? Just look at a real bookshelf. Do it like that. Click on the 'spine', and you can then see the front and back covers. I'd like to sort the bookshelf by a 'star' rating I assign myself, so I remember which ones I want to read next.
6. some correctly display the first page of the book as the thumbnail. Some display a stupid generic PDF logo. It makes you want to scream.
7. Microsoft does even worse, if you add a folder.jpg of the cover, it warps it into some ridiculous trapezoid, surrounded by so much whitespace you have to do lots of scrolling.
8. The Kindle DX has this stupid toggle button that sticks up so it's easily busted off.
Amazon got it (mostly) right with the ancient Kindle 3 (the keyboard one) and my beloved Kindle DX. I am very careful with the DX so I don't damage that button! I regularly buy their newer Kindles, and they just wind up in a drawer somewhere or given away as I go back to the old ones.
iBooks in the iPhone is pretty good, except for the small screen, which is uncomfortable for dedicated reading. The bookshelf view is barely acceptable, still making poor use of the screen real estate. I suppose getting an iPad would fix that. Battery life is an issue for it.