Wow, tough one. But I have to go with Taty. It's not just about talent or potential (both of which Talles Magno has in excess). It's about attitude, work rate, a lot of other things. We're just a much better side when he's on the pitch.
Maybe it would be different with a different supporting cast. But if I had to make the decision at the end of this season, assuming all things going forward remain equal, it would be him.