GSP greatest for skill. Conor greatest for excitement.Trash talk Conor is the current king, but in terms of actual fighting, he is far from the King, last time I checked it's the fighting ability that matters. PPV sales, trash talk, that is the biznis side, true MMA, the guy has a long way to go to even be top 5 p4p right now, alltime rank is way lower
Truth
Both two division champs, dominate fairly squarely no steroids, unlike Jones and Silva.
GSP has whipped every guy he's ever fought.
Conor breaks PPV records and has Performance bonuses in every UFC fight except the Holloway one, where he tore his knee.
When you talk about GSP and Conor, you're talking about greatness. There is more than one path to greatness, both achieved greatness through different paths.