Primates of Power together - one for each Origin in the game.
ARC is the Faction that does things differently, and their Leader models are no different in that. For other Teams, especially in mid-Level size games, there will be thoughts about taking a Powerhouse or a Leader, but probably not both until Encounter Level 12 or above. For the ARC, because their Leaders are only Level 1, that is much less of an issue;. There other things to consider though. The Level 3 leaders typically mix up some attack Actions with buffing Actions and Powers, whereas the Primates of Power are not at all hard-hitting, but do offer team and solo Supreme buffs, so functionally are a quite different to other Leaders. If an when more ARC models are added, it amy be that the ARC is able to effectively use a wider array of Leader Card options than other Teams, which could well be another bonus.