Fire giants have been nerfed alot in attack, and so don't have a whole lot of power anymore, but their huge 80% peirce armor makes them extremly effective versus archers. Get 2, and they can slaughter the archers with their range. Tox, slings, cheiros, arcae, peltast, chariot archers, are all beaten badly by the fire giant with that awesome pierce armor.
But, the collosus is much better overall, as they are incredibly cheap in TT and are generally alot more powerful against anything. But you are comparing myth across civs, so I am not surprised one of these beats up the other so well.
Oh, fire giants have a bonus versus myth units, collosues don't, but collosus large attack make up for it. Fire giants actually have an attack special, collosus don't.
Nick: Eten.
Gods: All of them!
Vanilla.