I have sailed on RCL ,NCL, HA, Princess and Celebrity. I have to say they are more alike than different. I started on RCL in 1991 so I am one of the old people cruising on their ships. Many of us started on RCL so have at least Diamond status and will cruise for the perks. I have been on Celebrity more of late but I did a NCL Haven in November and loved it. I will have my first suite on Celebrity in June so I will be interested to see how they compare with NCL Haven. My comment on the mega ships is that they are fun on TA’s . So much to do and plenty of places to people watch. Their lack of outdoor space is not a problem as TA’s can be cold and windy.