Royal Caribbean is where you want to go. Carnival is like a knock off. I went on a snorkeling/scuba with carnival and it was pretty disappointing. Aside from the free beer at the end they kind of took us in circles. I saw the same lobster, crabs, sponges, & fish like 5 times. I spoiled myself in going on the Royal first. I know for a fact that I won't be going on Carnival ever again. The Royal is a lot bigger, cleaner, and a bit more classy. I plan on trying out the other cruise lines this summer. But Royal is definitely my favorite so far