Some of the overblown nonsense went away after 4.1.
Android can be faster but not smoother.
It can lag but not from Android itself, but the skins OEM's put on it. But iPhones generally have better GPU and better optimization. Also iOS does LESS in the background.
It's worth noting that since iOS 7 and the introduction of background app refresh, there is less of a gap than before between the capabilities of the multitasking systems in iOS and Android. iOS retains its' smoothness though.