When written well, and not like a doofus, USAgent can easily stalemate Cap. Stark has more experience in the armor, but Rhodey has more fighting experience overall. As he was in Vietnam last I checked (he seems to be one of the few with a static background, unless Ellis gets his hands on him or something, which would be okay) and Stark was just an arms dealer in Desert Storm.
Yes, Johny Walker once told Hawkeye that "what is a guy like you gonna do against a guy that can press 10 tons".
USAgent and Warmachine are both quite a bit more powerful than Cap and Ironman, but I gotta give it to the latter with their experiance. Cap has shown he can take down a more powerful Agent on many occasions using his superior fighting abilities (but has also ran like a scared chicked from him too fearing what Agent is capable of doing)
Sorry then, he's only class 20 then. After his beat down at the hands of Protocide (in Cap volume 3) his strength was augmented and doubled to expediate his healing process. I thought the page I'd used to find his strength had listed his original level (it said 20, so I thought, doubled it should be 40, right?), but it was updated without me noticing (and thus 20 is the final sum). Sorry for the confusion.