We were on the Wonder for the most recent NYE cruise and it was a lot of fun. The NYE party on deck starts at about 10:30 with lots of music, dancing, and character appearances. Near midnight, waiters come out with trays of complimentary Champaign, faux Champaign, and hors d'oeuvres.
DCL provides party hats, and every stateroom received a DCL print.
Two years ago we were on the same cruise and Broadway performer Susan Egan (original Belle on Broadway) was on the cruise as a featured entertainer. She was great! This year we had Mark Wills who is a washed-up country musician.