We did the Magic out of NYC last June and our first NCL in December - the Epic.
DCL is a different experience because it is Disney. The shows were good (maybe one was very good) - not Broadway quality as I'd read but my daughter didn't care as long as she got to see the characters. The food and our experience in the MDR were just okay. I was not blown away by either - hated having to be at dinner every night at a certain time and missed the choice of a buffet at night. Liked our room but did think it was a little tired/worn (ready for dry dock). My daughter would not stay in the kids club which was a little disappointing. I thought she would enjoy it. She did love the princesses, who were wonderful with her - probably the best part of the trip. The ports were pretty lame - Nassau, Port Canaveral, and CC (the best of the 3). I didn't find enough to do for adults and really felt that if we didn't spend as much time on line waiting for character photos, we'd not have had a lot to do. The price from NYC - way overpriced. (Our upcoming Fantasy with air - same category - is considerably less expensive than the Magic.)
I loved the Epic. The shows were good - and fun. The food was very good. Enjoyed anytime dining and the option of a very varied buffet at dinner. Room was nice - a little smaller than DCL - but nice (wasn't freaked out by the bathroom). My daughter did go to the kids club - in fact she asked to go frequently. Breakfast with Spongebob and Patrick was quite a lot of fun.
Ports were fun (St. Martin, St. Thomas, Nassau). Plenty to do for the adults (including a casino - yay). Loved the pool deck and the live music. I would be hard-pressed to find something that I really did not like about the Epic (maybe smoke in the casino). Price was about 60-70% of the Magic cruise - comparitable category. Were not nickeled and dimed - don't do soda.
I find it ridiculous for people who have not sailed NCL in 10+ years, even 5+ years, to weigh in on this question. Cruisers are very brand-loyal (the Disney cruisers and the Carnival cruisers seem to be the most....uh, "loyal"). Life is about choices. I would definitely give NCL a try. We're going on the brand-new Breakaway in about a month and I CANNOT wait. The choices of shows - and food!!! - look amazing. And oh yes, Spongebob and Patrick will be waiting! I'm really looking forward to Bermuda as well. I'd book on any of the upcoming new NCL ships.
We're also going on the Fantasy in December. Looking forward to that as well. I'll only do DCL as long as my daughter is into it. Won't be worth the $$ after that. Figure we have 1 or 2 more to go with DCL. Just wish they'd get some better itineraries!
Happy Cruising!