I, too, am an advocate of the MacBook (considering it's my first Mac) but for your situation, I'd say go pro. Let me quantify that by saying it's about durability. Although I have no problem with saying that the MacBook build quality is pretty good (although, some would argue not up to normal Apple standards), the MBP is a rock. Since you want this computer to last you for a good while, I think that's one of the main criteria you'll want to look at.
As for speed, both machines are blazing fast and you'll notice that right off the bat. As Houltmac said, they're also both very upgradable, at least in terms of RAM and hard drive. As for the screen, I personally thought the 13" would be rather small. Trust me, you'd get used to it. It actually feels pretty big right about now
