I think that fight would definitely go to Silva, either way. He could probably win on leg kicks alone.
Must we go over this again? RJJ would beat Silva badly in boxing. Silva would probably kill (yes, literally) Jones in MMA.
Why does it constantly have to be debated? MMA is not Boxing. It is like comparing football and basketball because they both use a ball. RJJ in a boxing ring owns him. Sliva owns Roy in MMA. It's simple folks. Use your brain to figure out the basic questions. Two different skill sets.