We have sailed in the Haven twice. ( 2 bedroom villa). Service was good not great. We did sail in an Owners suite ( NCL Sun). Service was better, but still not great. Entertainment was outstanding. Cagney’s was great. Buffet quality was poor. Ship was crowded, loud, and we did not enjoy the smoke from the casino. NCL let non Haven guests to use area, mostly families of Haven guests. This made it crowded.
I do think we got better service in other areas of the ship because we were in a suite.
We have sailed in FV, Concierge, Sky Suites and last sailing in a Celebrity Suite. All cruises on Celebrity have been great. Last cruise 8/27/2021, Luminae was outstanding. If I did not like what was on menu, they would adjust to my taste. There was also the option to order off the kids menu that had a great filet that you could cut with your fork ! DH wanted a baked potato and steak-not on menu no problem.
Casino no smoking so that is a plus. Retreat lounge, we used it a few times. Never many guests.
Martini bar fun,fun. Guests were treated great no matter where their cabin was..
So if NCL had a super great itinerary, I would book the Haven. Never a regular cabin.
But the clear winner for us and our tastes and likes is Celebrity.