Hi Paul,
I think this depends on your definition of powerful. If you are interested in media watching/listening/websuring. I hear the iPhone is better. But if you are a business user, or a personal user like myself who isn't a touchscreen kind of guy, my BB Bold is far and away the leader.
Don't forget the power comes from its user too. What good is 5 megapixel camera phone for if you don't use it to take pictures? And what good is a touchscreen if you can't comfortablly use it for text or email?