Wait...Are we talking best foot unit in terms of cost effectiveness/Turn Production? Or best foot unit?

Spartans. Is their armor rating really that low? Even then 40 Spartans could probably take 80 chosen archers. How many spartans can you kill with a unit of archers from a range? Also my spartans can deaden a cav charge. Bowmen Arent as good as stopping cataphracts. Or chariots for that matter.