There are a few great things about group interviews! First, you get a chance to "breathe" between questions, because everyone gets asked a single question in turn (at least, that's how it was at Touro-MI). If you see yourself going "off track" with an answer, you have a chance to get right back on track with the next interviewer... whereas in a 1 on 1 format, the interviewer would keep digging and pushing until you had completely buried yourself.
Second, by watching how the other students answer and how their answer is recieved you can not only figure out what things the interviewer is interested in or favors, but you can judge your performance in comparison to others by watching how interviewers react (this was my favorite part). I liked being able to come out of the interview with my opinions on how it went, and compare notes with the other interviewees.
Problematically for everyone else, i'm talkative has heck, and time is limited... You end up with less time when you figure out that they're going a 1-hour interview with 5 people, compared to other schools' 1hr 1-person interviews. 🙁