As someone running a 600MHZ phone running cm7 (coming from an iphone 3GS), I never noticed any lag, in fact it runs better than 3GS and iOS. The dreadful UI you continuously bring up, has never been an issue and never got in the way of doing what I need to do. In fact there are things about Android's UI that are superior to iOS IMO. Most of what you call good UI is probably subjective. I'd rather have google focus on bigger issues than, a marginal improvement in scrolling. What android phone did you use and for how long ?