Personally I haven't haven't hada chance to play with it yet. I will more tonight some quick thoughts on what I've been reading/hearing today.
- A lot of failed install attempts
- Takes a long time. Over an hour? It basically backup up your iPhone and wipes it clean then installs the new iOS 5 then restores from your last backup. So be sure to set aside some time because you don't want ot disconnect while in the process.
- Lots of new mini features like LED alerts, Custom sounds and alerts, iMessages, Reminders...