I've always beleved PED's can take you up one level. Fringy to a bench guy, bench guy to platoon starter, platoon guy to starter, starter to all star, all star to star, star to super star, super star to immortal. Like Fed says, it's not a magic shot that turns quad a players into Barry Bonds, you have to already be Bonds to begin with. Braun is obviously a tremendous talent. If you think he's going to fall off the shelf and become Delmon Young, well, you're nuts.
I think the biggest benefits aside from raw power is injury recovery & longevity. Clemens, Bonds, Palmeiro etc playing at such a high level at such old ages is an obvious clue.