Blackberry 9360 or iPhone 3GS?

I have an iPhone 3GS at the moment but I've been wondering wether a Blackberry 9360 would be better. I'm 13 and all of my friends have Blackberrys and bbm so I was just wondering what you think would be best.
Answers are greatly appreciated, Thank you!

The iPhone is better anyway you put it. You & your friends can download WhatsApp which is much like BBM but can work on other platforms as well.

There's so much to an iPhone vs a BlackBerry which only has BBM.