The best thing about Ironcap Spearmen is how tanky you can get them to be for such a cheap unit, they hold off ranged really well, and can stall melee a long time, as well as having the unique ability to cleanse negative effects when in formation, like fire. When they're in melee though, you could put them in a V (attack) state and spread them out, further increasing the time it takes for the enemies to go through all of them.