I installed iOS 5 on my iPad 2 as soon as it was available. I'm noticing a nice fix that I haven't seen mentioned anywhere. Prior to this upgrade when my iPad was sleeping for a significant amount of time, when I opened the smart cover the backlight would immediately turn on at full brightness and then dim to a very low level. To get it back to normal I would have to touch the screen, it was annoying but not a major issue. I am happy to report that with the update to iOS 5 this bug has been fixed. My iPad now wakes at normal brightness every time.