Nicole, although family member did not apply to MGH, I did do a course-by-course comparison between NYMC's and MGH's (neurogenic track) curriculum and they were very similar. MGH covered a couple of extra literacy courses and NYMC covered slightly more medically-oriented courses. NYMC also covered a seminar in counseling that I didn't notice in MGH's curriculum. They both also require 70+ credits to graduate. With NYMC, you also graduate with TSSLD certification, which you'll need to teach in NYC or do any hospital work that receives any gov funding, as I understand it. Other than that, I would say, go to the one that you prefer. They are both expensive without funding. If you got a scholarship to MGH, that is very hard to pass up, not to mention it has an excellent reputation.
On a side note, everyone says to go with the less expensive option, but not sure how much it applies if you're interested in working in a medical setting. Have you heard about NYMC's reputation among employers? Are their graduates usually sought after for medical SLP work in NYC?