These programs (I would also throw Scripps Post-Bac in there, although it is a much smaller program) have a very high acceptance rate into medical school--however it's also something to think about whether or not it is the students in the program that gain acceptance, or if it's the program that gets the student acceptances. Maybe it's a bit of both, but I'm pretty sure (at least in my program) most of these people would have gotten into med school with or without their post-bac program. That's not to say there aren't benefits to such a program (there definitely is, and I'm positive it's one of the best decisions I've ever made), but don't get into the mode of thinking that it's the school that will get you in. You have to work to get yourself in, and nothing is guaranteed.
These types of programs tend to pick students who will probably succeed with or without the program (with 1-2 charity cases...like me..hahaha...). The average GPA of my post bac class was a 3.7, and the average SAT breakdown was 710 reading and 690 math or something like that. Many of them have also done some crazy things in their past careers (olympic cyclist, wall st, published writer, etc)