Just my 2 cents as a current student who had that reservation beforehand, you won't even notice the size of the class once you start. There's plenty of faculty to go around, and the small groups will ensure that you have a core 8-10 classmates that you are really close with (academically, at least). In terms of friends, it just means more to choose from, but no matter what school you attend you'll probably have a small core group anyway.
Yes, it seems like a drawback and my friends in other med schools always have the "gasp" reaction when I tell them our class size. But for all practical purposes, it doesn't really make a difference. You aren't going to be good friends with all ~100 classmates at any other school, and it's no different here. That being said, with 250 people you still recognize everyone and smile at each other in the street, even if you're not particularly well-acquainted with each other. After all, you'll spend 3-5 hours a day in the same lecture hall 5 days a week.
In my humblest opinion, it's just one more number that we think about during the application stage that has no noticeable effect on the actual med school experience. If you liked what you saw here during your interview day in terms of the atmosphere and student happiness, don't let the class size deter you. The students you met were the way they were in spite of (because of?) the class size.
Either way, good luck in the decision process!