I can give you my perspective of BU MAMS, as I am a first year MAMS student.
First off I want to say that I absolutely love BU. The facilities are top notch! The faculty are among the best in what they do, and they are superbly supportive of their students. Our advisors as well as the course directors really care about how you do in the program. The program, just like any other SMP, requires a lot of work but it is doable.
One of the great things about the progam is that classes such as Biochem have these clinical session lectures where you get to correlate everything you are learning and see how it relate with diseases that doctors are actually encountering.
I was accepted to TUFTS MBS, Georgetowns SMP, and BU and I chose BU because of its reputation, excellence, and overall feel when I visited BU.
In regards to UMDNJ, I do not know a lot about the program but I would say with confidence that BU is the better choice if you are trying to go to a med school that isnt UMDNJ.
If you have any other questions feel free to PM me.