To be honest, I think there are times when various approaches are effective, and other times when they are not. When I wanted to make quick progress, I did doubles (5 days a week) for four years straight. It was brutal but got to where I wanted to be. Now I do one 1.25 hour workout per day and just go as heavy as I can, focusing on one body part per workout (i.e., bi's and tri's on separate days). I just go thru all body parts and then start over.
p.s. I was natural throughout, if I was juicing I would of been insane looking, I am positive about that.