First, whismcott does better for beat up as then it can support it with tailwind or taunt. Metal burst doesn't get negative priority, so you need to go against faster pokemon for it to do damage. One bulky water that counters it is swampert, as it resists thunder wave and returns back with earthquake. Its so slow that metal burst has no effect on it.
P.S. Am I seeing double?































LeafGreen 



HeartGold 



















White 2 












































