Quote Originally Posted by napoleon526
Heavy Billmen are OK units, I usually keep a few in my English armies. They're very effective against militia and spear units. I have noticed though that they are vulnerable to cheap units with the "effective against armor" trait. These include Ceitherne, Highlanders, Highland Archers, and other axe-armed units. Heavy Billmen will usually defeat these units, but they'll take an irritating number of casualties.

I don't use them in battle lines though, since they're very vulnerable to cavalry charges. Which is dumb, since the billhook was used as an anti-cavalry weapon (the billman would use the hook to unhorse heavily armored knights). I suppose their ineffectiveness vs. cavalry is to avoid making them a super-unit.
they work fine against cavalry, in a melee. its the charge that they can't take.