Just returned from a 7 day cruise to St. Martin, St. Thomas and Nassau. We were looking forward to experiencing the "super-sized" vessel. We've cruised once on Celebrity to Alaska and then been with NCL in Hawaii, Mexico and Western Europe.
Flew into Ft. Lauderdale/Hollywood, primarily because of Southwest. Arranged shuttle with SAS who provided superlative service to and from Miami cruise terminal. Embarkation was hassle-free. Based on the signs, it appeared you can enter the terminal as early as 10 (and I noticed people were already checking in at about that time yesterday as we were waiting for our ride back to the airport). We went directly on board on arrival a little after noon and went to Garden Buffet for lunch and to wait for rooms to open up - 14th deck was ready at 1:45.
Our 10 year old thoroughly enjoyed the children's program and was able to enjoy the freedom of checking in and out herself at this "tween" age. We all liked the waterslides and deck area - there seem to be enough chairs. The buffet was excellent and able to accommodate the crowds - didn't do any dinners there but expect it was the same.
Concur with other comments about ship movement - minimal seas but it seemed to rock/roll out of proportion which makes me wonder what it could have been like. In addition, there were pops and noise from the walls on every roll that actually made it hard to sleep a couple of nights - I think they were due to how the walls/furniture are connected (or not!) to the ship's structure.
The ship was full or nearly so. Show reservations were fully booked by the second day. Some said they'd made reservations via internet but I don't even recall finding that feature with NCL - would recommend you look and do it that way or make the box office outside the Epic Theater one of your first stops.
We had one meal at Le Bistro which was very nice (as it should be for the $30 pp surcharge). While we enjoyed the shows, including the 11 pm comic/magician David Williamson, we actually preferred the live singing/dancing troupes than the "Vegas" shows - partly because of the crowds and hassle factor but also because these shows aren't Vegas caliber or length yet seem to be presented with the same hype.
Except for getting ashore in Nassau, getting on/off in port was easy.
I don't think we will cruise on the Epic again - while there is more space (inordinately devoted perhaps to the casino and shops - there essentially is no library, for example), the number of people make the main dining rooms even less personal, less intimate contact with crew and fellow passengers and, in general more hassles due to the masses.