In response to your question regarding theory at Massart, Arsenic, I don't know enough to say.
I agree with lightswitch in that I rarely came across Massart graduates in Boston, though it seems reasonable that many of those already living in MA, attending school in-state, would stay and work there. So perhaps the SMFA presence was only more salient due to personal relevance... still, from my experience SMFA is well connected within the local art scene.
True that the school communities are separate and mostly insular, but not antagonistic towards each other, I don't think. I lived with Massart students and in turn attended shows, events, etc that I wouldn't have known about otherwise. And while cross-registration at other schools is possible, it involves lots more effort to orchestrate - so I maintain that the SMFA/Tufts partnership offers a greater breadth of academic courses easily accessible to students. But if you'll be in the studio all the time and are happy with Massart's offerings (which are certainly solid), this disparity doesn't matter.
As for the quality of mfa student work, yeah, it varied. The good stuff was pretty fucking good, though. Also, I think SMFA likes taking students who come from other fields of study, which sometimes means their work is less developed coming in. I don't know if SMFA is *more* conceptually driven, only that it is *invariably* conceptually driven. Given your stated interests and concerns, I feel Massart would be a better fit for you.