We are a family of 7.....Me, DH and 5 kids. Currently our kids are DS 20, DD 19, DD 18, twin DD's 10. We have been sailing with our kids since our 3rd child was 3 and our twins took their first cruise with us when they were 8 months old. So we have sailed with kids ranging from 8 months old to 20 years old..and pretty much every age in between. We are all platinum Disney cruisers. We've also sailed a few times on Carnival, NCL and Royal Caribbean. Disney is still by far our favorite (even for my adult kids and for me/DH). After that, I think I'd rank Carnival next. Royal Caribbean's bigger ships have some great features that we enjoy (specifically the Royal Promenade and the Flowrider), but as a whole I think the nod goes to Carnival because of better food and because my youngest 2 like the kid's programming better on Carnival than on Royal Caribbean. We also enjoyed the 2 pool deck bars on Carnival and the variety of comedians/piano bar/trivia. We had a great family cruise on the Norwegian Epic (great entertainment options back when we cruised on her). Our other NCL cruise was the Sky (we were invited on for a post wedding celebration) and that was a total booze cruise with people that had way too much to drink everywhere (but that is to be expected on a cheap weekend cruise out of Miami).
Like I said above, Disney is still our favorite, but when we have ventured away for Disney (for a cheaper trip or a different itinerary or for a cruise that fit our schedule) we have never really been unhappy. We just go in realizing that we can't expect Disney and enjoy the vacation for what it is...and it's always a good time.
Jess