This is a tough one. Gyarados is a beast, it looks destructive and cool plus it has a rare red form. Milotic is a beautiful sea serpent? Not really sure what she is, but she is beautiful, useful in Contests, and harder to get than Gyarados. Gyarados has Dragon type and water type offensive moves while Milotic has healing, stabilizing and attacking moves. This is really tough, Their very evenly matched and I love them both. But I say Milotic because I like her by a tiny bit more and she can stabilize you with sweetkiss+attract then kill you with Surf.