My wife and I have sailed the six larger cruiselines mentioned by many. Carnival, Princess, Royal, Holland, NCL, and Celebrity have made up the majority of our cruises (63 to date). We've enjoyed every one of them, often for different reasons (food, a special server, new "play" options onboard, layout), so I won't denigrate NCL or any of these companies.
What we are learning is that as we age (we are 64 and 60), is that we appreciate the more sedate atmosphere, and the more mature passengers, we see on Holland and Celebrity. We like to dress up, so Holland gala nights are fun, and we like the Music corridor on many Holland ships.
NCL has been fun when we go with our kids or large groups, but it is quite active, at times crowded, and the dining does need some pre-planning to get best value.
Any cruise is awesome, but Holland and Celebrity seem to be fitting us better now. We utilize balcony rooms on most cruises, and have only done suites a few times on Royal (where we have Diamond Plus status).