I sailed on the MSC Fantasia with my husband and 3 children ages 7, 9, and 10. My daughter ended up breaking her foot a couple of days before our vacation and ended up using a wheelchair and crutches throughout our cruise, in order to get around. Here is a list of pro and cons
PROS:
-Kids sail free
Great room with a great balcony - quiet except when kids were running up and down the halls all hours of the night
Do this on your own and use the train system to get on and off.