Well it was a whole array of things. I believe you shouldn't choose a school just because it is well known or "established." You need to choose a school you feel will provide you with the optimal environment to learn and grow, a school that is suited for you and makes you comfortable. You could go to Johns Hopkins and come out a crappy doctor or do horrible on your boards just because you ignored the cut-throat environment just for the name. So although UMDNJ and KCUMB are considered "top tier" DO schools by the majority, CUSOM to me was a better fit.
For me, I was looking for a school that had/did the following. A school that still uses human cadavers - a lot of schools are turning toward computer simulators as they are more cost effective - I believe the best way to learn anatomy is through real human cadavers. A medical school affiliated with an established academic university - because this allows the med student access to all of the undergrad amenities as well as provides more state/public funds to the med program. And I was also looking for a strong experienced faculty, established clerkship sites, extracurricular medical opportunities, and an up-to-date facility.
CUSOM met every single one of my requirements, with the exception of a good track record (board pass rates and residency match lists) as they are a new school and non-existent. However, after seeing all of the other criteria met, the track record did not become a factor because I feel confident CUSOM will become one of the top DO programs in the nation (in time of course). Affiliated with the undergrad Campbell University, established 2x the amount of clerkship sites than there are 1st year students, set up optional week long international medical trips, in the process of setting up a student-run clinic to treat the local community, a brand new state of the art medical building (the designs are gorgeous by the way), numerous amounts of donations, faculty from Duke Medical School, PCOM, and other top notch programs, and the list goes on.
I hope this helps your decision. haha