There was a time in MMA history where people honestly weren't sure who was better, Jose Aldo or Jon Jones.
In 2011 Jon Jones captured the UFC LHW championship belt, becoming the youngest Zuffa era fighter to hold gold at 23.
Two years earlier Jose Aldo destroyed Micheal Thomas Brown to become the youngest ever Zuffa champion (WEC) at 23.
Aldo went on a 9 fight win streak from there, beating the likes Frankie Edgar, Chad Mendes x2, Kenny Florian and Uriah Faber. And with the exception of the second Mendes fight, none of then were particularly close. Aldos takedown defense was the stuff of legends, and long with his hands, knees and jabs - his only weakness at the time was the tendency to lead with his rear hand wildly and his poor gas tank. He was talked about in the same sentences as Jones, GSP, Fedor and Anderson - the four guys everyone with a brain acknowledge as being objectively better than everyone else.
Then came Conor, who tortured him with world play for what seemed like a full year world tour, and then stopped him in thirteen seconds. What came after were a myriad of lower body injuries the mysterious abduction of his low kicks, some more reported than others then two curb stompings by Max Holloway. But none of that takes away from the fact that the peak of Aldo's career was nearly as high as anyones in the sports history
People legitimately pick Renato and Stephen's over him in recent fights before he showed that even one foot out the door hes still easily a top 5 type FW fighter.
He recently posted that he wants to fight out his current contract and retire. Dude will retire a legend, and one of the 15 best MMA fighters to place them up and inarguably one of the two or three best FWs ever.