I use iBooks a lot for school, I can access my course information online and then open .pdf files of notes, handouts, etc in iBooks, you know like how you're supposed to? Well after updating to iOS 5, none of my files are in iBooks anymore. When I try to "open in iBooks" from Safari, iBooks opens but the files aren't there. So far I am NOT impressed with iOS 5. My iPad still isn't working entirely normally but that's a whole different issue. This OS and latest version of iTunes both seem to be as unstable as Windows! Ugh!