I've been accepted and am going to MSIH!
What influenced my decision is a few factors, the biggest probably being the global health focus (small seminars, 4th year international electives, etc). I also appreciate the small class size and ultimately, the opportunity to live in a unique, foreign country with a really diverse population, which I figure should make for a really interesting experience.
It doesn't hurt that MSIH enables you to do 4th year electives at Columbia, and also that it has a pretty great record of matching to some impressive residencies. I mean, it's probably not the school for you if you want to go into some super competitive specialty, but I've always planned on going into primary care (as I believe much of their student body does).