I downloaded the blackberry kindle app from amazon a couple of weeks ago. It is very cool, and free, which makes it even better.
My only other experience with ebooks is my ipaq, an HP pda. The ebooks I read on that were usually freebies from the project gutenberg website. The ipaq served that purpose pretty well, but getting the files on it was a bit of a pain. The screen is a nice size for ebook reading but there was a lot of scrolling involved.
Kindle for blackberry is an easier process. I can connect to amazon and download what I want in a minute or so. The instant delivery thing is quite nice. And I can page down with the space bar button instead of having to scroll.
Now for the suck part. If you download books and you have to exchange your phone like I did (bluetooth was defective), you lose your whole library.
When I received my exchange phone, I went through the whole blackberry desktop backup procedure. It transferred almost everything to the new phone and cleared off the old blackberry.
I was in the middle of reading an ebook when I requested an exchange for the phone. So I checked the kindle app to see if the book transferred. It appeared so. Joy! Only, not. When I tried to open the book, it wouldn't let me. I downloaded another book, and it let me open that one.
I thought maybe if I deleted the kindle app and reinstalled, it would work. Nope. Then it didn't let me open either book. My theory is that the kindle software thinks I'm trying to open pirated files, which I assure you, I'm not.
These two books were offered for free when I first downloaded them. They are no longer free. If I want to read the rest of Bite Me, I will have to pay for it.
My biggest concern, though, is what if I had paid for a bunch of books? I would have lost them. I didn't consult amazon customer support, so I can't really tell you if there was some resolution they would have offered. For me, the problem just isn't that deep. It's not like I paid for the books in the first place.
Free is free though, so I guess I can't whine too much.