RCI definitely. Sorry, just can't stomach Carnival. There are many reasons, but mostly because RCI offers a little nicer experience. If you're in your 20's and just want to party, go for Carnival. Otherwise, RCI offers tons of activities in addition to having a more mature atmosphere on absolutely incredible ships. Have fun!
Spring Break and Carnival spells trouble. Actually Spring Break and any vacation where Spring Breakers go spells trouble.
P.S. We have sailed 3 Carnival cruises and loved them. I am not a Carnival basher. Just think Spring Break tends to bring out a "livelier" crowd.
My very first cruise was on Carnival, unfortunately, I didn't realize it was also during Spring Break. I had a great time on board, of course, I had nothing to compare it to either. WAY TOO MANY drunks, and I mean drunks, not buzzed. Too loud and just not something I would enjoy. By the way, I was 19 at the time, and I still thought it was too rowdy for me.
I would strongly recommend RCI...they have tons of activites for all age levels especially teens. We are going with our family again in two weeks, and the ages range from 9 to 19 and then from 27 to 60. You'll never be bored, and the experience with RCI will be what you expect and more from cruising.
Definitely RCI Don't have kids, have friends that do, and RCI is so much better for both the adult and the teen crowd. It is more upscale, nobody running down the hallways howling like coyotes at 2 in the morning with the purser offering you earplugs when you complain. Everybody can have a great time without offending other passengers. (And I like to party, I just don't like to keep everybody in my hallway awake while I am having a good time).
I have to say that my first cruise was on the Carnival Imagination and I had a wonerful time!! My balcony room was 350 sq. feet compared to the 179 sq. feet I have booked on the Brilliance. I wanted to try RCCL. The ship truly looks beautiful. I was on the Carnival on school vacation and it was not bad at all. I also believe I will not find the same pizza on RCCL. I had 7 pieces one night!!!!
I would add my voice to trying to book on a Voyager class with RCCL- we took our then 12 and 10 year olds in 2000 and they had the best holiday of their lives. We are booked for the Navigator in March of 2003 (our Spring break).
A couple of comparisons. I cruised both lines within a 4 month period. First, Carnival has diversified the age of their guests to a point one third are 55 plus, one third under thirty and the rest in between. This can be different during school vacations, etc. True longer cruises the ages go up on all lines. Carnival cabins are about 30% larger. Entertainment and service about the same. Food in Carnival's dining room is noticeable better. RCI's isn't bad, just not memorable or special. Buffets on all lines I think are about the same. Both have excellent youth programs. And pricing is within about $100 of one another.