My 16-year-old daughter and I just sailed with extended family on the Jewel out of NYC. Having never been on a cruise ship, based on the reviews posted here and pictures of the ship, I was expecting a cheezy, bad-food-filled, surly serviced, perpetual up-sell experience, but what I found was way different.
First, the ship looks MUCH better than it photographs. It does not actually resemble a Vegas performer's tastelessly-decorated RV. The cabin we had was small but well put together so that it didn't feel too tight (full disclosure: I live in a Manhattan apt). The staff who work on the ship are really, really excited to be there, and super nice. This was a pleasant surprise. The entertainment was the high point - we saw a great magician, an excellent house band, and a lot of other good quality performers. The mood set by the staff, performers and cruise director is fun, friendly and light without manifesting the kind of institutional aggressive cheerfulness that makes me want to run away screaming. The gym was great and not too crowded, and the up-sell was either absent or quite low key.
The food: We ate at a couple of the cover charge restaurants, and only the steakhouse was at all worth it. Save your money - the free buffet offers a great salad bar, a good carvery, good grill, good desserts and outstanding fresh fruit. I saw a lot of people piling plates with mystery foods that I would not consider eating - "oriental" stir fries, "Indian" food, all kinds of icky-looking stuff in casserole dishes. I saw a lot of plates of this stuff left behind on tables, and I'm guessing these folks probably complained about the food quality. You can assemble a menu out of what is available there that is actually quite good. The all-you-can-eat Norwegian smoked salmon offered every day for breakfast was outstanding. While I'm on salmon, my only complaint: you cannot get grilled/seared salmon at any restaurant on this ship that isn't overcooked to rock-hard. Don't even try it, they will promise you that it is only seared on the outside... they lie.
Overall, I was sold on cruising as a holiday, and would go back to this ship and line. My parents, who cruise all the time, said they prefer Holland America, but they loved the entertainment on this one and the whole free-style thing. This is a great way to holiday, and I felt like NCL really went the extra mile to make sure it was a great experience. I was impressed with the whole thing.