6 time cruiser; been aboard Norwegian (good), Royal Caribbean, and Carnival (very good). The Serenade wasn't a bad ship or unclean, but the food was cafeteria quality at best. (You'll need a lot of salt and ketchup!) The entertainment was basically the same show with some variation night after night. The guest service was inattentive to the point that just stopped asking for an extension chord for our stateroom and eventually canceled a plate of chocolate dipped strawberries that I had pre-ordered to be in our room when we arrived but wasn't there (canceled on the third day after begging for them!)
Been on 2 Royal Caribbean ships but won't be on a third. Norwegian I would do again but by far my most satisfactory cruises have been on Carnival ships.