Arc troopers are elite front line troopers, and commandos are black ops behind the lines. Although ARC troopers can go on stealthy missions to, their usually on the front line destroying thousands of droids. Commandos are behind the lines stealthy, assassinating high priority targets, gathering intel, and ll that type of stuff. Arc troopers are more independent while commandos operate as a team.
Commandos use prototype weaponry while ARCs don't.
I don't know who would win, but I think there almost evenly skilled and easily as cool
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