I didn't use until 3-4 years but I could have made much better progress naturally with the knowledge I have now.
Back in the late 80's and early 90's the publicized training routines sucked. No one ever showed me how to squat or deadlift and I never saw anyone deadlift before I just started trying them on my own. If someone knowledgable would have been around I would have made much better gains and might never have even tried the stuff - not that I look upon it as a regret.
I think lots of beginner and intm. lifters use juice due to dissatisfaction with their results. Personally I doubt the majority are training very well (they probably still believe it's 90% diet), and they would get better gains with less gear if they learned more first.