There is one more site called "Magical Journeys" that specializes in all Disney vacations, including cruises. They have helped me on discounts for Disneyworld vacations, including several after I was already booked.

We have taken two Disney cruises and have another booked. They are outstanding in every way. We don't even have young kids-- we cruised the mediterranean this summer with our 24 and 21 year olds, and cruised the western Caribbean with just my wife and me a couple of years ago. The only time it was ever crowded was during the Pirate night theme party on the top deck. Otherwise there was always plenty of room. Also, we traveled in the winter and there weren't even that many young kids on board since there wasn't a school break. So don't worry that this is a mess of screaming kids. It's a wonderful relaxing vacation. Enjoy.