The battery on my 4S had been alright but not great on 5.0 but updating to 5.0.1 made it significantly worse. A difference of 20-30% more drain per day was what I was averaging after the update. I went to my local Apple Store to have a Genius check it out. She said that restoring it and setting it up as a new phone would fix the problem. According to her, I shouldn't restore from a backup because any corrupted files could be carried over to the backup. This is something I not heard before. Can anyone confirm that setting it up as a new phone would make a difference with the battery?