I was one of the surprised ones after the CocoaHeads meeting. Throughout the entire presentation using Instruments and other stuff I had assumed you were using your MBP.

I considered a 13", but ended up with the very bottom of the line, an 11" without even the no-brainer $100 memory upgrade. Part of me was being cheap, part of me was almost daring the machine to be good enough. And it's been great. Perfectly adequate for my personal programming projects. I suspect not powerful enough for my work stuff, but I consider that a feature. :)