I love my M&P10 and never had a problem with it that I didn't cause. The AR10 platform, while not standardized like the AR15, is a good general purpose rifle. It will do most anything you would want to do with a rifle, though it may be over kill on some things.

DMPS is ok but heavy. I'm not sure on the Ruger but I think it's even more proprietary than the S&W. I don't think any of them would be a bad buy but being that I own a S&W and this is a S&W forum, I lean to the S&W.