I'm with HoreTore on this one. For the time when Bills show up, they are a stroke of battlefield genius, especially since they're even cheaper to get than basic Levy Spearmen. The important points would be: try to avoid using them to take walls (they die like crazy to the tower fire - use a shielded unit instead), and don't let cavalry or archers have their way with the billmen, either wrecks them easily (again from lack of a shield). Preferably use them as flankers (this is especially useful in cities as they maneuver the streets infinitely better than cav) or they can be used as shock troops since their charge is very high. They break most early infantry units quite well, which makes them the perfect opposite of England's low level spears, who OTOH are better at wall taking, eating missiles, and stopping cav. They are, however, awful at killing other infantry, which is precisely what you should hire bills to do instead. You will of course tech up beyond them at some point, but as growth is lowered in 1.2 you should now get a good amount of use out of Billmen as primary melee troops until you can actually get to anything better. Of course England should also lean on archers a lot early since longbows are available, and an army full of primarily longbows and billmen is a winning combination, as in HoreTore's example. I would personally probably want a few spears somewhere in there, but you definitely shouldn't do without the archers or the bills.