As far as the on-screen animations, I have noticed that iOS 4.2.1 on my iPhone 4 is now running a bit slow and choppy. When I installed iOS 4.2.1, I reinstalled the phone to its base factory settings, so it was a clean install. I also restart my phone almost every day. The phone started out fine, but after a week and a half of use, I've come to the conclusion that iOS 4.2 just isn't as fluid as 4.1, which sucks. It's the only problem I have with the OS, as everything else is just peachy. Unfortunately, I HATE choppy animations on what is supposed to be one of the fastest smart phones on the market. iOS 4.2 is making my brand new iPhone 4 seem antiquated. This post in the Apple forums seems to have people with similar experiences. Although I disagree with the arguments that it is unstable (mine has been extremely stable) I do agree that the OS is now very choppy when opening icons, pinching and zooming, and swiping. http://discussions.apple.com/thread.jspa?threadID=2663348&start=0&tstart=0 To me, iOS 4 needs another update. Ughh.