I wasn't applying to medical school, but during my conversations with graduate admissions coordinators, several people mentioned my BYU degree very positively, and talked about how impressive they thought the economics program there was. It didn't get me into Harvard, but I was happy with where I ended up.

That's just my experience, though. Maybe things are totally different for medicine. Especially since it seemed like half of the BYU student body when I was there were planning on becoming doctors.