We picked this line and ship based on other reviews and the fact Norwegian was including alcohol and specialty dining with the package (and based on other cruises, it ended up saving us about $1,200 in the end). Some of the reviews were alarming, so we went in with some caution about being overly excited, however, the cruise overall was great with some things not so well done (and let's face it - they cannot be perfect trying to accommodated 4000+ passengers).
The rooms are pretty standard in terms of other ships. I did appreciate having a coffee maker in the room (something that a few other ships on other lines have not had), and there was ample storage space (under the couch, on the desk, under the bed, and a large closet space. The ship is well appointed, with dark "wood" hallways/doors to the cabins. Stairscases on either end have large mirrors, and overall, the ship was well maintained, felt very new (it pretty much is) and was easy to navigate.
The "extras" on this ship include two waterslides that you free fall from to start (so much fun) and a tube slide (also a great experience) that has a clear plastic piece that hangs off the edge of the ship. The ropes course was scary and exciting all at the same time, and the multiple sun decks offered ample, quieter space away from the pool. This ships also has a large kid's water park area (one of the drawbacks is the number of kids on the ship, but they've done a good job creating kid-friendly spaces for them nonetheless). The best feature, in my opinion, is the promenade (deck 8). It has large walkways, ample seating (couches, chairs), and many of the restaurants and bars spill out with additional tables at which you may dine.
Miami port is easy to navigate and plenty of taxis/buses available.
Typical cruise ship port - 5 ships in port equals way too many people. Didn't feel overly safe either.