Pros
Fun coworkers. Made long lasting friends even after the internship ended. Very good experience overall and allowed for some unique experiences that you cannot get in college.
Cons
Some departments at least give you a chance at applying for a full time job, others simply use you for cheap labor with the fake promise of, "If you work hard enough, you might get a full time job" when that was obviously never their intention. Unfortunate to see some interns go through that.