We basically wanted to try Norwegian to compare them to their sister company Regent (we cruised with them earlier this year). Took advantage of as many offers as we could to compare apples to apples. Conclusion, Norwegian is good, but just can't match Regent's service or quality - and this is important, take all expenses into account, and the difference in price is not that much.
The ship is huge with many shows and restaurants. I think the entertainment was generally better than most other cruises I've experience and that may be a function of being on a ship of 4000 passengers. Our cabin was decent size (a mini suite) with the best storage we'd ever seen. There were cabinets and drawers everywhere! But only one electrical outlet! WTH? Good thing I brought my converter, which allowed us a couple of extra plugs. In these days of electronic devices and on a modern ship, there's no excuse to have swap and share outlets. Further, speaking of electricity, our room's lighting was far too weak for over 50 eyes (especially over the sink, where you need it most.) Our bed was comfy and the sheets and towels nice.
Food was variable. Some excellent - especially Cagney's steakhouse and the Italian restaurant. However, several dishes in the Manhattan room were decidedly average. I don't think a customer should have to pay extra for good food.
See my notes above. Great storage and adequate space. Inadequate electrical outlets and weak lighting.
Very good guide and great sight seeing. Monaco is the high rent district.
Best most passionate tour guide ever. Must do in Barcelona is Sacred Family.