Well, Josh, my vote would be for NMH. I have two sons who have attend (one a current student). My older son checked out many other schools (possibly every major east coast boarding school) and NMH was his hands-down favorite. His younger brother refused to even look anywhere else because he was already in love with the school. I can't compare because I do not know St. Mark's, but I do know that the academics and faculty at NMH are top-notch, as are the athletics and the arts. In addition, this is a truly caring community. And, the campus is gorgeous. Any questions, feel free to PM me.