One example: Android still doesn't use the GPU for the interface, so the scrolling on a brand-new Nexus S still isn't as smooth as on a three-plus year old iPhone 2G. Plus, the lists don't bounce at the end, so not only is it choppier but it's (slightly) disconcerting to hit the end of a list as well (maybe the Gingerbread green flashes will help here, but a bounce just is more natural).

(This is not to say I only like Apple things. I think that Windows Phone 7 has the best and most consistent UI/UX of them all, currently, and webOS is quite nice as well.)