I was using my iphone 4 with some lower version but two days ago I upgraded it to IOS 4.1.It took little bit long time but finally it finished successfully. But after upgradtion I am feeling that my mobile is working slowly. Some applications, like iBook application working very slowly. It is not as smooth as it was before upgrading. I am planning to going back my previous versions because I fell IOS 4 is not as good as I was dreaming. Is anyone here who is having same experience?