I was surprised at how long it took to "restore" the phone after iOS 5 was installed. It was as if everything (apps, videos, music) were being synced back, but over Wifi (which is enable by default, so maybe that's why the restore takes so long??).
Been playing with it for a few hours on my 3Gs. Got the camera app to lock up. I took a photo, then pressed the little snapshot icon of your last photo in the lower left corner and started browsing old photos. I pressed the blue camera icon in the bottom left to return to the camera to take another picture and the screen just went black. I can hit home and go back to the home screen or switch to another app but when I go back to the camera app, the screen is still black. I've double-tapped the screen and swiped just to make sure I'm not looking at a picture of nothing, but to no avail. Pressing volume up takes a picture (which does appear in the Photos app), but I still get no viewfinder/live preview in the Camera app.
Also, has anyone else noticed that you can't move the Newsstand app into a folder? Or is that just on a 3Gs. I tried to move it to my "Reading" folder where I keep Kindle and iBooks, but Newsstand wasn't having any of that!