Mang0 100% for me. He's God to the Gods, and when he's sandbagging he's just a plain ol' God.
That may sound like hyperbole, but he is the only truly consistently unpredictable player while at the same time being brutally efficient. Every quirky choice he makes seems to be the most optimal, and he makes them at the perfect times. Commentators will talk about the style of a player, but really style can be a bad thing because it means you know how they play their character and what moves and movement to expect. Being able to change playstyles and mindset at a moments notice and perceive that something isn't working and adapt instantly is the most important trait to have. Mang0 doesn't have a style, he has styles.
He also seems to have that Super Saiyan potential like Isai where he could just turn it on if he wanted to and make other top players look like casuals. Most of the time he's hiding it, but every once in a while we see his true form like when he obliterated Fly Amanita at Press Start (sorry Fly, you amazing boo).
k? lol
p.s. Mango is also the most delicious fruit to ever exist. S tier produce.