Things like Facebook's Chat heads only work fully in Android (basically Messanger chats show up as a floating bubble no matter what app you're in[0])

I also like being able to configure my homescreen and having different keyboards (though the latter's shown up in iOS now)

There's some feature differentiation for sure, though iOS has the advantage on some things (I would kill for fingerprint unlock)

[0] http://www.technobuffalo.com/wp-content/uploads/2013/04/Face...