Maybe this info will help you guys in the Mewtwo forums. I'll give some detail into my interactions with M2k and his Mewtwo at Canada's largest event this past weekend. I'm a Pit main, wolf secondary.
In friendlies, I couldn't get more than 2 stocks off him as wolf. In tournament we did Pit v Marth twice, then I CPed stadium and went Wolf. He switched to Mewtwo and 3 stocked me handily. He basically killed me off every single grab no questions asked. Uthrow, SH (Delay) DJC fair, regrab, uthrow -> whatever you want. That combo is super consistent and not that difficult so it seems pretty foolproof (and you all know M2k is the king of efficiency). If uthrow sent me on a platform, he would techchase with fair which worked better than any other aerial. Fair's increased knockback made it so that when I crouch-canceled after being sent on the platform (even as low as 30%) the fair grounded me instantly for a free techchase. Ultimately CCing didn't help at all against fair techchase on platforms even at low percents (very very key). He would sometimes teleport fair if he couldn't reach me in time as well.
When we talked afterwards he stressed that he thinks Mewtwo is at his best against fastfallers and that he gets mauled by floaties most of the time (this is true in Melee as well). His grabs don't provide too much damage outside of the FFers (Fox / Falco / Wolf / Falcon) and its tougher to edge-guard floatier characters by virtue of their non-linear recoveries. We both agreed that Mewtwo was better than his melee counterpart but still suffers from a few of the same weaknesses.
Also floating out and double or triple bairing is near impossible to avoid as space animals, take my word for it.
Hope this small insight was useful!