Fourie Dupreez named Best Scrumhalf ever by his international peers

https://rugby365.com/countries/australia/fourie-du-preez-the-worlds-best-scrumhalf-say-peers

I would agree with this. Better than Joost, George Gregan, Justin Marshall.
Joost was the better rugby player, but FDP was the best specialist 9. 

Morne is next.

He was one of the best but never better than Joost ,Gareth Edwards and maybe the recent youngster in France, Dupont. 

"Morne is next."

Strange deduction Moz, what game or games did he play at scrumhalf,?

I agree with Seb ! Joost was on a par with Gareth Edwards to my mind. 

Joost’s  head on tackle of Jonah Lomu changed the WC final. He was deceptively fast and strong.