The really crippling constraint on iOS is the keyboard. After using Swype on Android for a while it is excruciatingly slow and tedious pecking out text one letter at a time on an iPhone.
I'm using an iPhone these days because that's the platform I develop for and I don't really miss the flexibility of the Android intents much generally but the chilling effect Apple's control can have on innovation is really glaringly obvious in the keyboard.