They're
combining the medical schools. I don't think it will take place if you were to be an M1 next academic year, but the curriculum, experiences and reputation will grow more and more similar (already very close).
I think RWJ will get the biggest perk first with the
new Rutgers medical school building opening on their campus prior to the completion of the merger.
IMO attending one or the other should come down to just where you want to live. The big perk of NJMS is ease to get into NYC which is important to some. I went to RWJ if any specific questions you can message.