What do you want to do with the Mac?
If you use Photoshop / CS / etc, the graphics card doesn't contribute much, so don't whine about GMA950.
If you use the Apple photo/video apps, that's another story.
For general processor-based stuff, the MB is faster in almost all cases.
If you play games, then I'd think the fact that the MacBook has an Intel processor and can run Windows games would override everything else about it.
Of course, if you want a 17" screen, it's going to cost....the person who paid $400 or whatever it was for their PB got a good deal, but I'm doubting it was a 17" (they didn't say).