As someone else suggested above, I find there are more similarities than differences. I have not found the food on Celebrity, at least in the main dining room, to be superior to that on NCL. But, as of the last time I cruised on Celebrity, they still had a night during each cruise that lobster was served in the MDR. I've enjoyed sailing on both line numerous times, but more on NCL. I'm not much of a nightlife person, so can't really offer much there.