No one can replace ozzy. This guy is more of a showman than a singer. His guitar performance is nice, but he doesn't have the voice that ozzy put out. 5/10 for voice, 8/10 for guitar sideshow tricks
I'm a fairly competent guitar player myself. I love Sabbath and Zakk...you, on the other hand, aren't on my radar. Maybe your version of this is better...
ha ha multiplied by infinity. lets see you play something better. He was ozzys guitar player for years and has full permission form ozzy to play theses songs.