My wife and I have only sailed on Princess in the pawst and this was our first time on Carnival. We had heard the rumours over the years, i.e. Carnival ships are floating parties filled with college students gone wild and drunken boors. Well as for that...yes we did encounter more drunks and people behaving badly compared to Princess cruising but not overly so.
1. Overall service was as good as Princess and in some cases (dining room) slightly better than Princess (this was a big surprise for us)
2. Shows were more entertaining