Old Macho here thinks Luffy Will dance around all of Ace's hits and one shots him lol, maybe if he didn't show his pure bias against Ace I would take him more seriously.Sitting on the fence here
Luffy would lose to Ace with just G2 or G3, but G4 beats Ace, but he wouldn't be able to oneshot Ace until he actually reaches the top tier
Personally I see it as a tie or a victory either way