i know geiger and this guy don maclean both got busted for testing positive during drug tests, and got suspended for a time.
Also, a friend f mine worked out with geiger and he told me that the dude was a madman in the weightroom.
this leads me to believe that yes some do juice, but if they do Id have to say that it pretty much the centers and power forwards. everyone else has to be quick and any bulk would make it harder for them.. I could see shaq on gear, but never muggsy bogues or even jordan.