Just like few of the members here have said, the best / easiest way to crush M Mewtwo EX decks is with the new M Gardevoir EX (STS). The 2 energy Despair Ray attack OHKO's him.
This past weekend I went to a LC and out of 5 rounds I faced 3 M Mewtwo Decks. Deck 1 and 3 I had problems setting my...