To me, that is like comparing a Motel 6 to a Marriott. They both have beds so you can sleep. They have bathrooms and you can usually get breakfast at both. So needs are met. The difference is how refined they are. Young 20-30 somethings that want to party hard will love Carnival as long as they are not serious foodies. It was the first cruise I ever took and it hooked me on cruising. People that aren't as much into the hairy chest, hairy legs, and wet t-shirt type contests may not enjoy it as much. Both cruise lines have their fans. That is what is neat about cruising. There's pretty much something for everyone. Demographics vary a lot. I prefer a more refined experience so I go on Celebrity. Out of over 75 cruises, I have gone 3 times on Carnival, the last being last fall. Sometimes it is hard to pass up super cheap prices. Just manage your expectations. However, if it is one of those once in a lifetime cruises, I would pass on Carnival, regardless the cost.