Plain and simple, it won't run amazing because of the integrated graphics card. Some have said it runs fine and others say it runs horribly. If you really plan on gaming with your portable, go with the MacBook Pro. I however do not game that much on my MacBook Pro, it is for work/school. When I was experimenting with games under Windows on a friends MacBook, I found most games did not run very well. My Pro however handled them greatly because of the dedicated 8600M. So please go Pro if you plan on gaming.
And if I'm not mistaken do the new MacBooks not use the same integrated chip set as the previous generation? I know the ones before had a GMA950, but last gen has the same as the current generation I believe. So this question has most likley been asked before.