I'll just say what I said on another forum when I streamed that show live....
Ozzy seems to have replaced Zakk with a Zakk wannabe.
Gus seems to be playing more in that vein though, he's not normally so pinch happy from what I know of.
Gus played a good set I guess, but absolutely didnt put his mark on any of the songs, I think he must have been given a live bootleg of Ozzy and Zakk to learn the songs or something, because he was using Zakk's fills, especially for I Don't Know. And went pinch crazy, I was hoping he'd do better tbh, but by no means bad, he absolutely has the chops to play those songs.
I think given a few more shows...and uhh...Sharon and Ozzy's blessing, he'll put his own twist on the songs.