The whole debate with naps is in regards to gains, you don't retain as much water with naposim as you do with some other 'dirtier' dbols (such as thai's or russian dbol) I personally like them for that reason, the pharmaceutical grade of naps is very high compared to some of the other dbols out there. Hands down though I think the best dbol is Polish Metanabol made by Jelfa, that is some crazy strong shit!!
and very clean too, Jelfa has a good reputation for quality control.