As far as I've noticed. It was just changed, don't think you even be a choice in it.
So far the best points I've found are
siri - works a treat now, even with handsfree system in the car it's brilliant!
Turn by turn
safari speeds etc.
personally I'd prefer none of this Facebook integration, I'm not keen on that social network crud anyway. Even though it's not nessessary to sign in etc I just don't think it's needed.
Im glad they've just tweaked iOS, didn't need re building ground up, it works so just make it better/smoother