We sailed with our 2 young boys (6 and 3) on the Disney Fantasy October 27 - Nov 3.
First off, I highly recommend our travel agent Jennifer from Trip Guy travel...we use them for everything now and are great (email@example.com).
The ship was beautiful and very clean. The restaurants were very good, the rotational dining worked well. A highlight of the week was Animator's Palate, when Crush interacted with our kids.
We loved that our waiters rotated with us every night, Ned and his team really made things special, they really got to know our family.
Our kids loved the kids club, one suggestion for Disney, tone down the volume in there after 8pm, I found the rooms well staffed but overstimulating, too much high volume music blasting from different rooms, a bit overwhelming.
I loved the hand washing machines in the kids clubs, wish they had more of those around the ship.
If you are going to Costa Maya, consider booking a day at Maya Chan beach club. It was a perfect oasis from the cruise crowd...just a few families on a beautiful beach with amazing food and kayaks too.
Overall I'm very happy with cruised on the Fantasy, though I look forward to our next Disney trip being at the parks with the large swimming pools, maybe a combo package would have been better for us.