I'll give him this: He was polite, calm, cool, generous, and while often circling out on personal hyperbolics in giving answers, he always neatly circled back to tie it all in nicely with his official answer.
One thing I didn't like was how often when Walz was answering, he would be watching Walz then his eyes would turn to look straight at the camera.
The other thing was how Vance often failed to offer any emotion in his face, no inflection in his tone that the things he was talking about were important, concerning or exciting to him. He needs to work on that. This is one area where Trump wins in spades is in the ability to convey the emotional content to the viewer so that they can better relate to him.