Just wanted to add my two cents in on this topic for those of you traveling with families...
My husband and I have cruised each year for the last 5 years with our two boys (now 10 and 8 which makes them the most semi sefl-sufficient males as they will ever be - I'm realistic).
We just got back from our first NCL cruise (in 18 years) with the freestyle program and realized that this was our first cruise on which we NEVER ARGUED (okay at least about getting ready for dinner anyway).
We had NO STRESS about my getting myself and the boys dressed in time for dinner because dinner was whenever we wanted.
Having said that, I am thrilled to see Carnival offer the same style of dining and we are currently researching our first Carnival cruise (disappointed in NCl but let's not go there in this thread).
So, if you are cruising as a family, with children who still need to be herded along, and are planning to do a lot of stuff on board or shore excursions, I strongly recommend this style of dining. It's your vacation, you shouldn't have the stress of "moving the herd" to dinner on time.