We have only sailed 6 times. One with Dolphin (no longer exists) one with Costa, and the last 4 with Princess. We really enjoy Princess for two reasons. First, we like the personal choice dining. Gives us an opportunity to meet different people. Second, we really enjoy the fresh water pools. I do not enjoy swimming in salt water, unless I am on a beach. All other cruise lines have salt water pools. I think the exception might be RCCL Freedom of the Seas. Not sure, we've never sailed on her. Everyone has there favorite cruise lines, but ours, hands down so far is Princess.