Without knowing anything about your tastes and standards on cruising, I don't know how anyone could answer that question for you.
However, if you are used to RCCL's product I personally don't think the NCL Dream would meet your expectations. But, if you are willing to go into it with the mindset that it will be a different cruise experience, then you can find terrific price deals by sailing on NCL. Just don't expect them to be a match to RCCL in everyway.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013