We have been on 86 cruises prior to this one, mostly Royal Caribbean, but a fair number of NCL, Carnival, Celebrity and Princess as well, so we feel we gave a fair basis of comparison.
I'll begin with the positives: The cruise director, Ian, was one of the best we've had. Production shows and guest entertainers were top notch during the transatlantic portion of the cruise. As expected, the guest entertainers on the Baltic portion had more of an international flair...operatic, jugglers, acrobats, etc... that which can be equally appreciated in any language, and while it wasn't to my taste, we were so tired from touring that the entertainment was secondary.
The itinerary was absolutely amazing, with the overnight in St. Petersberg as the highlight. Berlin, Estonia, Stockholm, Helsinki also were a treat while in the Baltic. On the transatlantic, we stopped in Punta Delgado, Helsenberg, Dover.
The water was glass-like for the entire voyage. With mother nature's cooperation, it was smooth sailing all the way.
Now the negatives: The size of the inside cabin was comparable to what we generally see on the ships used for weekend cruises. On top of that, a bunk bed hung on the wall presented a hazard when getting up during the night. Prior to booking, we had called NCL to make sure that we didn't have a bunk bed in the room. They assured us that we didn't. When we went in the room and found that we did, we went to guest services where we were told, "You can still get off the ship."
Breakfast and lunch service in the Versailles and Blue Lagoon was poor. Wait time was extended. We were a party of four, and each of us seemed to be served on a different schedule. Coffee would be served without cream. Waiters avoided eye contact, so, by the time we got cream, the coffee was cold. Seats almost always had crumbs on them from the previous diners. Most servers very very friendly, but seemed to have trouble getting it right.
Evening meals were all in specialty restaurants. Food was good, but again there were service issues...some were serious. We were served way undercooked scallops twice. Our travel companions asked for medium rare steak, and received meat that was slightly seared on the outside, and RAW on the inside.
The Stardust Theater has broken springs for almost all seats. To find four unbroken seats in a row was nearly impossible.
The Spinnaker Lounge is too small to allow everyone wishing to attend events to be accommodated. Unless we arrived 1/2 hour before the start of some of the better events, it was either standing room or sitting behind a pole.
While we had a great cruise overall, it was not without lots of problems.