We sailed on the Dream in 2013 and thought it was a wonderful experience. In 2015 we sailed with Royal Caribbean and found it hard to choose between them. Now after this Western (changed after Hurricane Irma) Caribbean 7 Day on the Fantasy I now know that RC is the better choice for us.
For cruisers with children, perhaps this is a great experience, but for us without kids its just not a great value. RC has better food, variety, dining arrangements and dining locations. It pains me to say this, but RC also has better on-board entertainment and activities for adults. Additionally our spa interactions were weighed heavily with unwelcome add-on pressure.
On the positive side, Disney does have a great staff. We had to visit the medical center and they were very professional and caring. Embarkation and debarkation were a breeze.