@entropy_aegis: The OP didn't specify on DC or including Marvel, and besides in a straight up fight DC superheroes could still take him.
But the thing is with Batman this isn't a straight up fight. He doesn't have a huge ego. He wouldn't go out and tell everyone he is evil. He would take heroes out one by one and by the time anyone caught up with him most of the big guns would be down and out. Who ever caught up with him wouldn't be too powerful, because the powerful don't tend to be too smart in comics.
^i don't know why this is in bold.
Personally, i think Question would find out or Deadman (accidentally) would find out first.
When i was younger the quickest way that a superhero could gain respect in my eyes was if he could beat juggs. Not physically, because he's unstoppable, literally unstoppable and they would have to outsmart him.