I should preface this by saying I'm 68. So while I have sailed on Carnival and Norwegian, I will never do so again. I find the loud and boorish behavior on those two lines to be tiresome and annoying. They are plagued by first time cruisers who think getting drunk and talking the loudest is acceptable behavior.
I will stick with Celebrity (my favorite) and Royal Caribbean. Where you are most comfortable determines for me where you get the beat "value" for your money.