I've had the Galaxy S4 for a few days now so I'm fresh off the iPhone 5, which I still have.
So far I can say that it's true. Android versions of some of my favorite apps seem sluggish and choppy compared to the iOS version. Two examples are Spotify and Google Chrome but there are others where scrolling and touch input don't feel as instantaneous as my iPhone 5 or even my iPhone 4S.
That said some apps look better and have more options. Spotify again is a perfect example which has a very slick EQ. iOS does not have this option.