Deca used to be my favorite, but eventually led to good ole deca dick. It also gives me cystic acne. With deca, I think the biggest issue is that it builds up in your blood over time and keeps the levels elevated much more than NPP does. With NPP I have not had as much bloat, no cystic acne and no deca dick. So I'd say if you are running a low dose like 200 to 300mg per week, you may be fine with deca, but if you are looking to blast and older like myself, I'm 41, I just do better with shorter acting compounds and daily pokes these days. If I could handle deca at 600mg plus per week without the dick issues and acne, it is strongest of the two as far as gains.