See, the problem is, most sites show only DPS rather than DPS/TDO. For example, when you look for best Gengar counters (Like, in Pokemongoinfo), it shows Confusion/Psychic Mewtwo doing a full 100% damage in comparision to other mons. However, that's only it's DPS.
For my personal experience Soloing Machamp, Mewtwo does a good chunk of damage using Confusion, but it's so slow! You can't avoid anything. On the other hand, with Psycho cut, you do less damage but you can avoid and Charge your charged move faster. In PVP I always pick Psycho Cut over Confusion cause it's way faster and both don't have an important difference on damage output. (If you're using Shadow Ball, go for Psycho cut)