We have cruised with Norwegian and RCI, and crossed with Cunard, and were hoping that X would be more like Cunard. In most ways we were disappointed.
The Bayonne terminal is a work in progress, but we got on board promptly. Because we booked last minute all we could get was an inside cabin, and it was fine. Dining was unexceptional. Again because of our late reservation, we had to take "select" dining. We were told to avoid 6:30-7:30, but an 8 pm arrival the first evening still caused a 20 minute wait. Other evenings were better. Select also means upstairs seating, without the soaring ceilings or the ability to watch the occasional dining room entertainment. Food was fine, but presentation ranged from lovely (Israeli couscous wrapped in zucchini - my favorite dish of the week) to diner-quality (eggs and bacon or several sad-looking pieces of french toast just dumped on a plate with nary a bit of garnish). The cafeteria was the most poorly organized that I've seen - with options spread out over a large area (I'm vegetarian and had to make the whole circuit to find something to eat, unless I wanted to stick to pizza and salad; on several occasions every one of the "gourmet entrees" had meat, and even vegetarian-sounding choices like rice salad could have bits of ham or chicken). We only ate there when we had to - lunch on port days. There were better vegetarian options in the Solarium, but that is at the other end of the ship (across the pool area), so running there for food left my husband for a long while waiting. The desserts on average were very good, and the scones were among the best I've tasted (although the runny jam and whipped cream were poor accompaniments).
Evening entertainment was fine, but daytime, even on sea days, was lacking. There was gambling, and rowdy pool-side games,, but I was really hoping for some Cunard-style lectures, concerts, or performances. We got to hear the very funny captain give a talk, as well as an engineer and there was a cooking demo, but really very little else.
It was hard to find a quiet place to read and relax. The Solarium is surprisingly noisy, most public rooms have piped in music and frequent interruptions for kid activities, private parties, etc., and the lighting in the library is very poor for reading. The gym had loud pounding music, unpleasant since almost every patron was listening to his/her own music through earphones.
Overall, I'd have trouble differentiating this cruise from our Bahamas trips on RCI (or Norwegian). It wasn't terrible, but had little feel of upscale luxury. One exception was the wonderful art collection (NOT the generic stuff for auction - but the paintings, prints and sculptures decorating many areas). Here's an idea for a daytime activity - have tours of the artworks! I was telling table mates about the David Levinthal Barbie Polaroids in the shop area, and they had no idea he's a well known photographer.