RE: Is Mewtwo X still around?
Mewtwo isn't seen much, but he has more potential now than he did during DP-PT. The reason was that Dialga G was HUGE during that period, thus making it near worthless. However, Dialga G techs aren't common outside of DPL (I called it DathPika Lock. =p) so Mewtwo is a little bit more viable. Luxray can be a nuisance, but you can just send up Mewtwo again and watch their Basics become Bench sitters.
Mewtwo is a deadly force against SP decks not carrying Dialga G or some other anti-Mewtwo tech. Most SP decks still carry at least some tech for it, even if not Dialga G. (Like Ninetails in Luxape.)
However, Mewtwo is far superior to Rapidash. I can go Uxie X against Rapidash, while Mewtwo stops Uxie cold. Rapidash also is pitiful at attacking. At least Mewtwo might KO something. =/
Anyway, I see you are running a spread deck. In that case, you don't need Mewtwo. The spread hits any Bench-sitters. It could be hard against him, but be glad that Mewtwo isn't too great on offense, and your spread will get a few KOs if that's all you need to win.