I agree with you here. If Iron Man can keep his distance, he should pull off a victory. He could also use a hit and run tactic. Ben will crush him though if he gets him in a bearhug or something. But Iron Man has gone toe to toe with the Hulk, and also defeated the Hulk at least once I think, correct me if I'm wrong, but Iron Man takes it. 8 out of 10 times.
It's not likely he would, I was just saying that as a what if. I don't think Tony's dumb enough to get caught by Thing. Even if he did I think he could break out of it.