Both Royal Caribbean and Carnival require at least a nice black suit for formal evenings(linen, cotton, silk, or tropical weight worsted wool) in the main dining room, so if you don't have one you will need to get one. If you prefer a resort casual style you can either skip the dining room formal nights, which is usually the best food of the week in there, or you could go with NCL, which has resort casual all the time(though they do have one fancier specialty resteraunt(I know this isnt spelled correctly but I struggle with this word)). You can also have your cabin customized to your specifications(linens, mini-bar, fruit) on NCL. I have been researching these 3 lines myself and each has their stregnths. Carnival is about the nightlife, partying, and hanging by the pool. They aren't called funships for nothing. Royal Caribbean(especially the Freedom and Voyager class ships) are activities ships. NCL is all about cruising your way. I should also mention that the comedy shows on some of the NCL ships are by Second City, a premier comedy troupe out of New York City.