We've done the buffet many times - not anything I'd consider a long line - we always get right to the start and make our way down the line at a good pace. The food is good and we've always enjoyed it. My only complaint would probably be that I never am hungry enough to take advantage of it

If you've never done it, give it a shot. It's at least worth doing it once to form your own opinion. But you certainly can eat on the boat and then go for the party and drinks.