For us it was twice (Teppenyaki and Chin Chin) on the Jewel in Alaska last month. We also get a lunch and a late meal at the Blue Lagoon a few times.
I am not a big fan of Cagney's and Le Bistro, the meals just wern't that great.
I have not been to the Moderno (the Brazilian Chiaroscuro) yet but that is on my list.
I do feel the meals in the main dining room was good enough and is cruise quality.
And yes I would you take an NCL cruise even if they didn't have the specialty restaurants.