Mewtwo-EX is overhyped and overpriced. His first attack is good, but against cards like Reshiram BW and Chandelure NV, it takes tons of energy to OHKO them and, if you really break down his HP, you only have to do 85 damage per prize, because he gives up 2. 170/2=85. And, in addition to that, other attacks discard energy, like Blue Flare, Ozone Buster and Strong Volt. It should be easily defeated by Durant. So, overall, I give this card a 7/10, simply because he is easily fitted into just about any deck as a Tech, but that is his only use in my opinion.