Circuit Breaker is no joke.. She actually hurt Unicron, and was able to easily hack/control electronics, including using Transformers bodies to form her own gestalt.
I was going to put her against Ultron, but that would've been a completely unfair stomp in her favor..
Iron Man, I'm not sure about. She does have extreme resistance to harm, shrugging off or merely being dazed from being sliced by energo swords, hit by flying trucks, and shot by top tier Transformers weapons..