More info can be helpful... how tall are you? If under 6 ft I'd say look at the 650B options coming to market pretty heavily. Not that someone under 6ft cant ride 29er (I do) but I'm finding a slightly longer travel (120-140 instead of 80-100) are more "comfortable" and the 650b's handles the bumps as well but doesn't feel as long.
when you say "XC" are you fast and flowy trails or normal New England rocky/hilly trails (borderline All Mtn)
Here's my take.. all the bikes you listed are nice,.. down right good-great. But, I found with the bigger box names you pay more and get ,well, less.
KHS, Giant, Felt.. and other smaller companies are usually better equipped (bolt on parts) bikes for the same or less $$
My biggest gripe with the big names is the crappy wheels they all give stock. Example, friend just got a really nice ($3500) bike.. frame/suspension is down right awesome,.. but drive train and brakes are mediocre at best and the wheels are down right cheapo borderline junk.
now on the other hand, testing a bike is VERY important if you aren't like me and like playing with the mechanic of a bike to dial it in.
I could go on for hours LOL but of the 4 you've listed they are all good bikes and my choices are just about in the order you have them listed (thou maybe move the Rocky up above the C-dale)