Basically both are fantastic Pokemon with a total base stats of 600 each. I faced the same problem but now i would personally suggest Dragonite holding Yache/Persim Berry with the following moveset:
Outrage-STAB, great power, advantage of high atk., coverage against dragon types,high acc.
Hidden Power(Fire)/Flamethrower-high acc.,great power, main for coverage against ice types
Hurricane-STAB, great power, what else?
Earthquake-Used to deal with rockies,high acc. and great power
Garchomp is likewise great with speed and atk
i recommend the following moveset for Garchomp holding Yache berry
Earthquake-great power, STAB, high accuracy
Flamethrower-Powerful, high acc., deal with ice types
Stone Edge-Powerful, Gives edge over ice types
Well the decision to use either remains in your hands.