I give it to Ordo. I imagine that at the end of the day he will turn out to have stronger vassals, he also seem to be a bit smarter plus has more troops in this scenario.
Goba is the only one of the brothers that seem to be worth something. Bunen's sacrefice strategy can be effective, but is counterproductive if the enemy has number advantage. And Tork is a complete fodder. Rozo can win, if he turns it into a duel, but it's unlikely to happen, since none of them are the type that see duling as primary option.