Literally two of the best fighters of the century. Roman got his due, but Wonjongkam never did. His resume is a who's who. So many past or future world titlists, it's amazing.
In a vacuum I'd probably favour Gonzalez by a shade. Greater offensive variety and volume to give him a better argument in those close rounds. Pong was such a consummate ring master though. You couldn't count him out to find a way to keep the fight where he wants it and a pace that suits him better. Especially fighting in real world conditions in his homeland. He wasn't as strong or beastly as Borkohosor or Galaxy. Not as slick or athletic at Payakaroon. Probably not as technical or skilled as Kingpetch or Sahaprom. But he was no means lacking in any of these departments and put it all together quite well to have an insanely long and successful career.