http://www.gameplaybook.com/reviews/...w-iphone-ipad/
It was silky smooth on my iPhone 4 for the record and the speed and combos are all there.
Also, Inifinty Blade is amazing. Built on the Unreal Engine, it's a sword fighting game originally built for Kinnect, but it works so well on the screen and it is drop dead gorgeous. Could easily be a 360 game.