The exam blocks are pretty hard and you pretty much won't have a life the week before exams are scheduled. But you do have more time for fun after exams are over (as opposed to when you have exams once a week at other schools). I've never had a problem with the professors since I never really interacted with the professors outside of lecture.
The only downside about the larger class size is that it's harder to get to know everyone. During our pre-clinical classes, sometimes its hard to get a professor over to help you or to critique your work, but everyone seems to get by fine.
I'm a first year, and so far, our class seems to get along pretty well. Any complaints about Tufts are relatively minor and are things you would find at any other school. Tufts is a great school and they will train you to be a competent dentist in the end.