We've cruised NCL twice, once back in the 80s and then over Thanksgiving 2005. We've no children so I can't comment on that but we were very pleased with the Freestyle Cruising. There will be those who don't like it, and that's fine, but we were quite happy to decide what we wanted to eat that evening, make our reservation in the morning, and enjoy the rest of the day. Some of those restaurants require an upcharge, but with the deal we got on the suite we had extra money in our account to pay for them.
I really did enjoy the entertainment and having a casino onboard was great. I don't spend a lot of time gambling, but I enjoy it. I can't do that on Disney, but it also doesn't make it a deal breaker for Disney either (4th and 5th on DCL already booked).
The thing I really disliked about NCL was their bingo. Dislike is actually too nice. I hated it. I felt it was poorly run, the use of their bingo machines wasn't explained well, and it just seemed to be chaos. That said, I only played one session and it didn't ruin my cruise!
I would sail on them again in a heartbeat. Actually, I'd sail on most lines in a heartbeat (well, except easycruise; they're just scary!!!).
Michael