froyo has a lot of speed advantages. they probably did this because not many devices will be able to get android 3.0. Froyo makes even the G1 snappier but of course that phone doesn't have enough power to fully utilize Froyo. same thing happened on iOS. 3.0 the iPhone 3G was nice on but 4.0 lags. of course the 3GS handles both nice. the nexus one feels really nice.