I'm writing this from the perspective of someone who wants a relaxing cruise, as apposed to someone who wants to party. If you are looking to get, and stay, loud, this may be the ship for you. This is only my second cruise. My first was on the Carnival Fantasy, out of Mobile AL. The Fantasy was so great, that I couldn't remember everything that my wife and I loved about it when I wrote that review (amazing ship and crew regardless how old it is).
I want to start with the pros because I did generally enjoy my cruise, and it's not such a bad ship that I want to beet it down here. The staff are friendly and helpful, though they are obviously overloaded/understaffed. The food is good, and there is plenty of it. Our cabin was perfectly maintained. We had a party of 5, so we were constantly in and out of the cabin, and the crew worked around us beautifully. We only knew they were there because the room kept getting cleaned up, and they always said hello in passing.
Half Moon Cay is amazing. The beach is beautiful white sand as far out as you will want to go with crystal clear water. The beach is large enough that, even on a ship with several thousand passengers, it was easy to be off to ourselves. It's the one part of this cruise that was better than our last, and we went to Paradise Island on our last cruise. Before Half Mood Cay, we were sure Paradise Island was the greatest place on Earth.
This was the saving grace for our trip. My wife and I are beach people, so if a beach is just good enough we are happy. This place was amazing. The sand is perfectly white and smooth as far out as you want to swim. This is a no-shoes beach, even for the softest toes. The water is crystal clear. So clear that you want sunblock on your legs even if you plan to stay in the water the whole time (he says as he scratches the sunburned leg).
The beach is huge, so there is plenty of room for different types of people to spread out. If you are in to entertainment, and getting loud, Carnival has you covered. Right where you get off the boat they have a bar that I heard was nice, and the Cruise Director is there keeping everything hoppin. If you're like my wife and I, and you just want to relax on a quiet beach away from everyone, it's just a walk down the beach away and life is great. And, if you go that route, when it's time to eat there is a little road just on the other side of the trees and they run carts up and down it all day to haul you to the food and back to your hammocks.
Don't bother. We got off, pushed our way through all the people offering to braid our hair and get us cabs etc, and walked about 3 blocks in to the city before we decided that, at least at the port, Nassau was not worth it. We thought it may be a great time to be on the ship, while everyone else would be in Nassau. However, when we got back on it was still crowded. Apparently, a lot of people decided it wasn't worth the walk.