Jon has looked great. We'll see, though.
I don't think GSP is ever coming back and he left at the perfect time.
The only knock GSP has are a loss to Hughes and Serra and a controversial decision to Hendricks.
He wrecked Hughes twice and crushed Serra, so those hold little weight.
I see GSP Hendricks equivalent to Jones vs. Gus was to Jon.
Even though I would like to say Fedor, my more objective opinion would be GSP for the above reasons and because he dominated almost everyone he ever fought, which was always top contenders.