I upgraded yesterday with absolutely no problems. The longest part were the downloads, and all the installs were glitch free. YMMV, so it may be wise to pay attention to Stephen Green’s forecast for Friday when a million or so iPhones 4S come alive:
Folks, tomorrow is gonna be ugly. I don’t see how Apple gets this thing sorted out before the weekend is over. I’d be pleased as punch to be wrong, but mark my words: Tomorrow is gonna be ugly.