My husband and I cruised on the Norwegian Sky.
The ports of call were exceptional. The two excursions we booked with NCL were adequate as well. If you're looking for excursions that involve snorkeling and kayaking as we did then I guess it's best to use the "excursion" desk. However if you have researched where you would like to sightsee on an island then getting off the ship and hailing a taxi can be just as rewarding. We have been to many Caribbean islands and have always had great experiences with local drivers. They have lots of interesting information and generally cost less than booking with the ship. Remember the ship gets a cut. You can also have the satisfaction of knowing your putting your money straight into the hands that could use it most.
The service on the boat was adequate overall. If service was really exceptional we directly tipped the employee. I think it's more humane to include the tipping in the cost anyway and liked that NCL does it that way. On one day they ran out of ice-cream. The juice machines were out of service the entire cruise. The last night there were not enough color coded luggage tags for disembarkation. You have to ask yourself how can a business as large as this not know how much to order.
The food was adequate as well, sometime better than average. We somehow managed to try every eatery including the ones you pay extra for. Actually they were not significantly better then the other restaurants, but they did have a nice ambiance.
We had a balcony and it was great. I will never cruise again without one. It makes a huge difference.
My biggest complaint is with NCLs booking and Club ABC Tours. Although I booked the trip in Sept. 03. NCL did not book our air until March 22, 04. As a result our flying time went from 4 to 8 hours both ways with stop overs, when a multitude of direct flights exist. This was for spring break week. We were not able to get on the boat until 9PM, the boat left at 10PM. Going home we were trapped in the airport for 5 hours before out 8 hour flying time even began. Never let NCL book your air. It's all about the money.