My previous experience was all Windows until I got an iPad 8 months ago. Now I wouldn't be without it. Got a few new apps like Dragon Dictation, Office HD, Photo Transfer, PhotoAlbums, RDP and Pulse News. iTunes is advising me to upgrade from 4.2.1 to 4.3.5, but I am concerned that these Apple OS upgrades do not seem to go as smoothly as with Windows, and sometimes result in the loss of apps and/or data files. Right now, purchases are transferred, and sync is complete with iTunes on a Windows XP PC. Should I go ahead with this upgrade? What's the worst that could happen, and what would I have to do to recover. I'm still a beginner, so please answer in simple words.