This has been a hard one to call. I've gone back and forth several times. But I have finally reached a conclusion.
Maneuverability: This one has got to go to the Warthog. However, the Pitbull is pretty maneuverable for its build and size. But still, Warthog has the advantage here.
Firepower: Both vehicle's missiles and rockets do about the same damage. The Warthog may do a little more but it's to close to give an advantage in this category.
Accuracy: This one is a no-brainer. While the Warthog's rockets detach fast and easy from it's gun, the Pitbull's missiles are heat seeking. So they will almost never miss.
Armor: Obviously, the Wartog's strength is in it's speed and maneuverability. Not it's armor. The Pitbull however, has a decent amount of armor for it's class. So the advantage goes to the Pitbull here.
Speed: The Warthog is definitely faster than the Pitbull. But again, the Pitbull isn't trailing behing the Warthog by far.
My final verdict is: The Warthog, while able to maneuver around the Pitbull, isn't able to land enough shots on the Pitbull. The Pitbull however is able to land multiple shots on the warthog. The Pitbull's armor protects it from the few shots that it doesn't dodge. While the Warthog really has no protection against the Pitbull's missiles.
Winner: Pitbull(but actually, this was a close match for me)
Agree? Disagree? Say so in the comments. I will post my next match up soon.