article explains it all. NPP is a shorter ester... builds up faster and is out faster
NPP is a mild compound, its not going to make you angry like more androgenic compounds would.. so some guys think its not strong enough for them.. but if you are patient with it then its a great bulker
NPP is a much better alternative to Deca for those that PCT. You can recover easier since it clears quickly, unlike deca which hangs around forever making recovery an uphill battle