Did Syndrome ever target someone with his zero point energy from 500 yards away? Iron Man definitely has weapons with that range.
If they started closer together I'd say it's a quick draw.
__________________ Chicken Boo, what's the matter with you? You don't act like the other chickens do. You wear a disguise to look like human guys, but you're not a man you're a Chicken Boo.
Two main factors I see for giving Tony a win here:
1. They have full knowledge of each other
2. Tony has never faced an opponent like this
So, very little snarky discussion, very large amounts of missiles coming straight for Syndrome. We saw in Incredibles what happens when Syndrome gets taken by surprise by both his deathbot sphere thing in the city and Bob throwing a car at him. Iron Man has way more options than that robot or a thrown car.