Haaaahhaaaa.
This makes me laugh a little. Metagross is easy to beat you just have to find the back door to it. Look at me I hated Zapdos and every time he appears in a battle I always lose, but know I know how to beat him just like I did with Salamance and other pokemons. Don't hate a pokemon just because you can't beat it just learn abou him more and you will find the back door to it.
P.S= No offense