Like any other "expert" it depends on the experience of the person. Doesn't matter if it is fixing cars, picking out a fishing pole, or AAS. Your guy could be brilliant, or an idiot...who knows?

Since you are talking personal experience, I don't know a single body builder. All my info comes from here. Even then, you will sometimes get conflicting advice and you need to do research, pick an option, and see how it works for you.