I think Epic is a great ship to take at least one cruise on - but depending on your personal tastes of course.
The entertainment is really the best at sea. I liked Blue Man ( of course) but also Howl at the Moon, Legends and Second City. A lot of people rave over Fat Cats and I certainly understand why (the reason only I don't is because I play blues guitar and there isn't much in blue I haven't seen already), but if you are not a regular blue clubgoer you would find this really inspiring.
The food is good - especially if you try the alternative restaurants. But even the buffet is good. Great breakfast buffet with omelet stations for example.
O'Sheehans Pub is largely overlooked by the food is excellent, plus the selection of ales, and the game atmosphere makes it a really cool place just to hand out. I would say my favorite pub at sea.
And if you are single you cannot beat the studio staterooms.