It depends entirely on the game. In a slower tactical game the gamepad would be closer, especially if fast movements cause the cone of fire to spread. In a Quake style game where I can do a 180 and headshot someone with the railgun, the gamepad is woefully outmatched.
People can get really good at using a gamepad, but people can also get awesome at driving Mack Trucks. That doesn't mean they can take that truck and compete in Nascar.