Tablet pcs last only hours on battery while e-rink readers last for weeks.
That is true, but then again a windows tablet pc will - aside of reading - allow you to watch movies, listen music, surf the web, and even play Matrix games. Try that with a Kindle.
Also tablet pcs are backlighted so your eyes get tired.
Well, for me a backlighted device is more convenient. Works even with ebooks on my iPhone in a penumbrous room, where I otherwise would need glasses in order to read a real book. No argument here from my side, but I wonder why people claim that non-backlighted devices are eye-friendly, when they're used to spend most of their time on a pc anyway. I can work and play whole day without fatigue.
Other than watch movies and play games, you can surf the web and listen to music with a Kindle.
Most people who purchase a Kindle already have a computer or laptop or DVD player, so they can already watch movies and play Matrix games on other devices. I have never and most likely will never read a book on a traditional computer/laptop/netbook. The backlighting just kills me. But I haven't put the Kindle down since I got it, I am reading more now than I ever did.
An ebook reader is a purpose built device to read books and it does that very well, comparing it to a computer is like comparing a netbook to a desktop. Why buy a netbook, I can't play my flightsims on it when I can on my desktop. A netbook is designed to be highly portable and would not be expected to to the same things as a desktop, which is the same for ebook readers.
I just don't understand why people expect ebook readers to do the same as computer systems. They are designed to do different things.
I can understand the issue with price, but like all new technologies, prices will continue to decrease. The $489 price is for the DX, the "standard" Kindle (which is also useable in Australia) is a little over $200 now I think.