Ship
The first thing I'll say is that we were on the eighth floor, and had heard reports that it can get really loud up there at night, particularly from the scraping of chairs. While I could definitely hear it from time to time, it was never really bad, not even during the Pirate party when we went back early due to sleepy children. Unless you're a really light sleeper, this shouldn't be a problem.
What cabin did you have? I have been upgraded to a category 4 cabin for my September cruise, and while I am really excited to have the extra space, I am also really worried about noise!