Disney cruising is a cut above the rest. We've done Carnival and Royal Caribbean as well.
Our 5-year old was so impressed with every aspect of the cruise that his experience alone made it worth the (quite high) price of admission.
Aquaduck, Mickey's slide, the whole Castaway Cay setup, the three restaurants, ice-cream, Disney shows, pools with giant movie screen, Goofy's golf, detective game, pull-down bunk bed, and simply being spoiled rotten by the staff wherever he went, were the highlights for the kid. He didn't spend much time in the Oceaneers Club, though he did visit while we watched Avengers, and IMO it's a waste of the cruise to leave kids there to play rather than enjoy all the things they can do with their family on this remarkable ship.
Avengers 3D, Rain Forest area, Cabanas, and dinners served by those amazing waiters and the wonderful head server Ali from Turkey were appreciated by the parents. The Jamaican cabin host was also a joy.
Not much to complain about. It seems one of the families on board had kids suffering from gastroenteritis, something that can spread quickly in a warm pool and ruin vacations fast, and Disney restricted them to their cabin for the entire cruise - no fun for them, but considerate of other families. The crew were handing out disinfectant wipes everywhere around food areas.
Embarkation and debarkation were both super efficient. Getting there around 1:00 got us on board within about 20 minutes, right into the Enchanted Garden for the welcome lunch.
Pick up a Disney Dream beach towel if you go, it's usually on a "special" in the shops on board, and is a great souvenir of a fantastic vacation.