I have the 64GB 3rd generation iPod Touch which is running iOS 4.3.3. I really want to upgrade to iOS5. Has anyone had serious issues after updating? I have read about WiFi and battery problems but these may have been resolved in the latest software update. Anything I should know? It's running really well now. Also, I've read I will lose all my music, audiobooks, movies, and photos. What about my email? My iPod Touch backs up each time I connect it to the macbook air, but I would manually back it up before upgrading. If I find I have problems, can I revert to the previous iOS 4.3.3? I don't think I can. Thanks in advance!