I am leaning toward USAgent only because for him to go against Piledriver and whip his ass something serious then going toe to toe and talking trash at Ronan even after he got his costume fried off of him. Even Ronan says that he is quit the enduring hero for a human. Kree never gives humans any kinda respect.
I think Piledriver could take out Bane. I mean the guy has the power of an Asguardian denizen. Plus Bane took out Bat's but it was a bruised broken down, tired and overworked Bat's. Not a Bat's at his peak.
Agent carries, currently, either his razor-sharp, super durable star shield, or his photonic Eagle crest shield, which are both equally destructive with the proper application. He can't throw the eagle one though. He also has his energy truncheon, which can cut through reinforced steel, easily (it's basically a mini-light sabre). He also carries various conventional small-arms, an assault rifle, and a backup sidearm, probably a Colt.