I have both a 2011 13"MBP and a 2011 MBA and I prefer my Pro hands down everyday of the week. I think its just a better computer and as others have said people think its an inferior machine, well I don't and for me its perfect. I hate laptops with huge screens and like the 13" screen it has plenty of power for my photo and video editing plus its lightning fast. All in all I think its the perfect computer the i7 is great, I don't need quad core dual core is just fine for me. So when people pick on the 13 or say it doesn't deserve to be a pro I just move past it, compared to my Air the 13 is for sure a pro.
Wow looking at your signature you have the lot!
I have the 2010 C2D MBP with 8gb ram. I'm so surprised what it can handle in terms of processing speed, it's such a powerful little machine. Even hooking it up 2 a secondary screen causes it no notable problems. For people that have a laptop as their sole computer, the mbp still is the one