Well, both are good. DP is too big to get your identity highlighted there and NB is not so big yet that you get really famous. LOL.. It's not far better but better for sure. Reasons?
NB has lesser to NO spam
NB has got great and filtered webmasters ready to help.
Unique in look and feel. The most unique one as compared to all forums around
Alert Admins and dedicated moderators
NO negative reputation or infractions for members. Mods are here to weed out any negative stuff.
MB marketplace is at least working somehow and getting better everyday. DP marketplace is gone to almost zero level. Buyers hardly respond and scared of infractions and rules. Sellers hardly get good response.