To me end results matter, the rest is just specs and hype that sells cameras. I took both cameras with me in the field and whenever the chance arose I tested both. Armed with actual field knowledge and samples I concluded in the end the benefit is only marginal.
Real world, same lens, cropped 5DII vs. 7D, no meaningful IQ difference except the number of MP you're left with after cropping. Real world camera performance, 7D beats 5DII hands down for birds/wildlife.
Real world, FF camera with better performance (e.g. 5DIII, 1D X) and longer vs. 7D and shorter lens, no contest, 7D loses out.
Real world, can't afford longer lens on FF camera with better performance, shorter lens on 7D is still pretty damn good.