Neither, because both are decent people. As you say, either could easily beat most Sherdog posters. But neither is likely to want to do so. In fact, I suspect most Sherdoggers would be relieved when they realized it was a well known fighter coming down the dark alley towards them, someone with a lot to lose by attacking some stranger in a dark alley, rather than some criminal looking to rob them.
Maybe a better question would be that if you were being attacked by a couple of criminals in a back alley, would you rather have Cyborg or Nunes there to help you ...