i like both deca and npp. i get a lot of joint relief with either. the gains happen if i eat and eat and eat, otherwise, just strength gains. i also get deca-dick as well. No Peter Power isn't any fun when my sex drive is still there. pun intended.
i find using proviron, mast, caber, and a serm are helpful to counter-act deca-dick. it isn't so much i stay limp, but end up getting an erection then loosing it, without cumming. the add ons help.