It depends if your talking about Vanilla Factions or ones also added into it.
If by that than I'd say the Coalition, it's got history pre-dating the Zoners, they went from a Power dominating the Alliance to a bunch of ragtag saboteurs to a Mini-House and a fearsome reputation.
If your talking Vanilla than it's definitely the Zoners because frankly, they went from a bunch of 'crazies' living in between houses trying to survive without the major governments to practically a Mini-House in itself with a story of their own that is expanded upon in the mod.
