I used to have this reader when it was the original rocket ebook, back in 98 I believe. I forget the model, but the one I had did not have the modem. It was first generation. I had stopped using it when I purchased the franklin e-bookman. From what I remember, the battery life was fantastic and the display was excellent for reading. Better than any PDA that I have owned.
I dug it up a few weeks ago, but the battery would no longer hold a charge. Despite my efforts I could not find a way to replace the battery. I think I may purchase the ebookwise version. I currently own the Cybook, but would not mind having another reader. I am assuming that the ebookwise 1150 can still read the REB format.