Just got my PocketBook 360 from Forkosigan today, with pre-installed beta sofware as requested. Thanks!
The good thing is that you can choose between FBReader and Adobe Reader for EPUB, so you can use the (in my opinion, better) FBReader for books with no DRM. To open a book, hold down the OK (center) button a bit longer to get a context menu with "Open with" option to choose the reader. Previously opened books seem to open again with the chosen reader.