i think the biggie for me was the ability to use all of my lenses on all my cameras, whether it be my old 1977 fm, or my d90 i can the same lenses. with canon you have to have the latest greatest everything to use their high end lenses due to the mount switch in 85 for AF and the fact that they lack an aperture ring. i think the big reason why you see so many canons out there is because of the early digital race and the whole nikon AF fiasco of the 90's that they never bounced back from. either way its pretty much even now so it doesnt really matter as long as we all enjoy shooting.