For interviews, someone told me that most programs accept 1/4-1/2 of all interviewees. Then I've heard from the former upperclassmen at my school that interviews are really laid back and that they imagined that they didn't count for much (no one seemed to actually be evaluating them), so I don't know why they would invite so many people to interview and then not accept most of them unless they were actually evaluating them. For your personal statement, I've just heard that you shouldn't write it like you wrote you med school essay. The idea is not to stand out, don't try to be funny, don't try to be too unique. You just want to look like your a good, caring person who really wants to be a doctor and train at their program. Personal statements don't make, and usually don't break applications. Of course the better your personal statement is written, the more likely they are to accept you since that's part of your overall picture so it's not something that I would blow off, but it's not something that I think you need to have professionally done either (unless your a really bad writer). Don't talk about how important your outside life or family life is either, that will probably just tell program directors that you plan to take off whenever you can (this last sentence is my opinion, but the rest I've heard from senior people or read).