IMHO they are both the same. I am starting to believe that PEDs, in the hands of an elite fighters, are a bit worse. If a guy can throw 30 more EFFECTIVE punches per round he can do just as much if not worse damage than a guy with loaded gloves and normal endurance (who can tire over time). You get a guy tired enough and he couldn't hurt you with a baseball bat. You give a skilled fighter more strength, endurance, and aggression? You are in a world of hurt.
I think PEDS depends on the person. It will increase a persons attributes, but doesn't necessarily mean it will give you the edge if the other person is just that much better than you. Loaded gloves is like punching with bricks.....I say loaded gloves