The stats of the troops differ slightly, but not enough to make a noticeable difference. The faction troops aren't particularly unique, they all have the same base troops with one type of elite ashigaru (villager) troop and two types of elite samurai troops. However, NPC travellers will say that the factions never eliminate each other. They will fight for control of territory and are small enough that they can eliminate one another without the player's intervention. There are 20 factions in Gekokujo, up from 6 in native Warband.