No problems here, except I'm not going to be using a single one of those new features so if you don't feel like updating right now, then don't. The download takes like 2 hours .
Also some pages are not loading photos. Even the flickr app doesn't work.
find my iPhone will not be activated for a 3G(S)
AirPlay only interesting when you have Airport express or Apple TV. But when I am at home I better use the computer with remote on the ipad to stream and to controll.
AirPrint doesn't work with most of the network printers (I have a Canon )