jonneymendoza, the 7D has worse ISO performance than the 5D2, no doubt about it. 18mp on a cropped sensor vs 21mp on a full frame... the pixel density is vastly reduced with the 5D2 and that immediately lends itself to lower noise in the images. I have the 7D, my mate has the 5D2 and I'm always lusting over how 'clean' the images are.
Sure, the 7D is fantastic but not on the same level as the 5D2 for that sort of thing.
That said, I'm always going to beat him in getting the best shot in a sequence because I have twice as many shots per second