Have a wonderful time!
We have sailed RCCL,NCL and
DCL. we loved them all. I don't feel that DCL was superior to the others. It was different but not necessarily better. I think all 3 have their strong and weak points. In my opinion,RCL has far and away the best service- on multiple RCL cruises our dining room service was say,comparable to Palo,in the main dining rooms every night. The RCL staff continually went above and beyond,unsolicited by the way,to pamper us. NCL shines for teh beauty of its newer ships- especially the Dawn - and the gorgeous decor/layout,and also for the freestyle concept,which can add flexibility for families. DCL excels in family entertainment-the shows,the characters etc - and also its private island,which is the nicest we've seen.
All three were immaculate. As far as rooms go,DCL's room are a little bigger,but it's decieving. The DCL rooms are on the average bigger,but you pay more for it. And larger rooms/jr sutes etc are available on teh other lines,probably for a price similar to DCL. For instance off the top of my head our Radiance Cat C was similar in size or a little bigger than our Cat 6 on the Magic,and I think the price was similar.
So there's no reason you shouldn't have a wonderful cruise to Hawaii. There are lots of great options out there,,as good as DCL for slightly different reasons.
I would talk to your TA to find out what ships do the Hawaaiian itineraries. Then go to the cruisecritic.com boards and ask the people who have done these cruises how they liked it.