We have have done several cruises on both RCL and Carnival. When we plan a cruise, we take several things into consideration. In no particular order, the size of the ship, onboard amenities, the ship's port of departure, the ship's itinerary, the cost of the cruise, and what past guests have had to say about the ship we're considering. Unless we're planning a "ship specific" cruise, we tend to prefer Carnival. It's less expensive than RCL, the cabins are bigger, the food (IMO) is every bit as good (gotta love the almost 24 hr. pizza bar!), and, on a seven day cruise, Carnival has fewer days at sea with more ports of call, whereas RCL is just the opposite. Overall, we feel that Carnival has the best value for the money spent.