I was there a few months ago ...
I was in the same situation in May, and chose AUC. MUA is cheaper and has much smaller classes which I liked. I didn't like the fact that the admissions at MUA and SABA claimed the two schools to be the same just on different islands. Ie. if SABA is approved by CA as it is expected to be in the near future, MUA will NOT. Also, they tell you that the only states that they are not yet approved in are CA and NY, but be careful because some other states base their approval on recognition by NY and/or CA. If you know where you plan to practice call that state medical board and be sure they recognize MUA and that you can be licensed to practice there coming from MUA.
Best of Luck,
"Tin Cup"
"BE THE BALL"
- Chevy Chase