I've cruised both and like both for different reasons. RCL has a more upscale feel to their ships, while Carnival's are more Las Vegasy. The rooms on Carnival are larger and their bedding is much better. Food and service are about the same. I think Carnival has much more going on for activities. My kids preferred the Carnival children's program over the RCL one. We've found, generally, that the age group on RCL seems to be older while Carnival seems to be younger. We sailed the same week on different years on an RCL ship and a Carnival ship. There were definitely more kids and younger couples on the Carnival ship. Whichever you decide I'm sure you'll have a great cruise!