I used to do a lot of consulting work in the "cruise" business and you can take my word that you don't want to get anywhere near a Carnival ship.

They are always getting pulled over for violations, and they are always having health and safety issues, catching on fire and running into things.

My vote would be for Royal - I don't know about the crowd though - they ALL seem to cater to the older farts, single widows looking to pick up younger stewards....

Each cruise tends to be different and they always depend upon the group...