I don't have a Kindle reader, but I do have the Kindle app on my iPod Touch. I had the Touch for a while but never really thought about actually reading a book on that tiny little screen, but I gotta tell you, I am hooked... big time! I am reading more books now than I ever did!
For me, I think it has to be the fact that the text is lit from behind rather than being reflected off the page like with a "normal" book. I find it easier on these tired old eyes.
I don't know if you can use other "e-readers" on the Kindle, but I also use one called Stanza and the e-reader from Barnes & Noble.
And I totally agree with the fact that this thing will zap your bank account! I curse Amazon for their One Click buying! :twisted:
Oh, and I already informed my wife that I will be getting an iPad... sooner or later... probably by Christmas... if I can wait that long. Yeah, I drank the Apple Kool-Aid some time ago. There are some WiFi communications issues that they are working on so I am sure there will be a v2.0 very soon.
Enjoy your e-reader!