The most famous spinning kick knockout in MMA prior to this was when Edson Barboza landed a spinning heel kick that stiffened Terry Etim like a board at UFC 142.
The only loss in the UFC career of current Middleweight Champion Luke Rockhold was via a devastating spinning heel kick, courtesy of Vitor Belfort at UFC on FX: Belfort vs Rockhold.
One fighter who has been increasing in popularity because of his highlight reel of spinning kick knockouts is Michael “Venom” Page. Here he is landing a cleverly placed 360 tornado kick. Page currently fights for Bellator.
Regardless of what some purists might say about spinning kicks, they do work if done correctly. It is one of the flashiest techniques but also very useful in high level martial arts.