This decision really has to be your own, but it's helpful to look at reasons why other's picked the schools that they did. Personally Loma Linda was my top choice, but I never got in off the waitlist, and although I was accepted to Columbia, I went with Pitt in the end, and I don't really regret it. If you're wanting to see my thoughts, search for a thread by me called something like "Columbia vs. Pitt." If your situation was the same as mine, you've got about a week and a half to make one of the hardest decisions of your life - take my advice, and go with your gut.
If you have any questions about Pitt, feel free to call Dr. Etzel, the dean of student services. He's always happy to talk to students, so share with him your situation and thoughts, and he'll be a very straight shooter. I know talking to him really helped me make my decision.
Again, remember that anyone else's reasons for picking one school over another are solely their own, and the most important thing that counts is what you think. And like Boxer said, think back to interview day, you're walking around, taking the tour - which school really had you thinking "Wow, this is where I want to go." For me, that school was Pitt, for you, it could be another. Good luck, and remember, either way you choose, you've still made a good choice.