Just played around with my buddies 3GS, and wow. The background feature single-handedly killed every other smart phone on the market. Yes, I realize other phones can run apps in the background, but Apple did it properly. To see one app roll off screen to the left as another quickly rolls on from the right is just simply pleasing to watch. App switching on the 3GS is hitch free, I'm excited to see how well my iPhone 4 will do with twice the RAM.