My VCOM interview was my most laid back, and my favorite interview. Instead of having one interview with three or four people on one end of the table, and you on the other, with them alternating who asks you questions (WVSOM), the interview was one-on-one, with an individual from three different fields (med ed, clinical, and admin). You have up to 30 minutes with each person, and they just let you talk about whatever. We talked about topics ranging from what I do for fun, perceived differences between DOs and MDs (from the ever-popular "why do you want to be a DO?" question), to where I see medicine going in the next decade (socially and economically). One of my friends talked about caving for 30 minutes with one of his interviewers. The main purpose is just to see what type of person you are outside of the numbers on your application.
As far as the likelihood of acceptance with an interview, I think it's pretty high. Of the five people who interviewed with me, three of them are in my class now.