I was on the Evo 4G with Sprint (WiMax) before I purchased my iPhone 4S. The Evo 4G was fast and I was worried that I would suffer slower speeds when I switched to the iPhone. After doing several speed tests on the Evo 4G (WiMax) and the iPhone on Verizon (3G) I found the data speeds on the iPhone 4S to be faster than the Evo 4G, despite the fact that the iPhone 4S is a 3G device. I think it has a lot to do with how iOS handles traffic.