When I first heard the song opening, I thought...o my, a song from the No More Tears era....but that went to hell when the autotune shit kicked in. Maybe it is because I am not a teenage kid, but autotune vocals do NOT appeal to my ears. Cher did a lot of autotune late in her career, and I didn't listen to her either!!!
From my understanding, Ozzy's first verse was recorded separately at a remote location, so this isn't even a true duet by any means.
(source) As far as the collab between the rappers and Ozzy, I am ok with it. Music is universal. If the collab gets young listeners to check out Ozzy (and metal music), then it's a win-win.
Will I put this song on my playlist, HELL NO. I have no intentions of checking out Post Malone even if his past is rooted in guitar and metalcore.
On a side note: Ozzy did sound good for his age and all the health issues he has had the past year. His voice was solid and strong.