I went to college near there and dated several Berklee guys. At that time anyway (longer ago than I care to admit) the curriculum was heavily into jazz. Not sure how rewarding it would be for folky mandolin, but as I say, it was a long time ago. I do tend to agree with Maryrrf's impression, though. Anyway, Berklee has a fine reputation - are you near enough to Boston to get to any of their student performances?