He was usually fine when I've seen him live. Although the last time was Ozzfest 1998. It was his TV appearances that I was mainly referring to. Sharon Osbourne turning him into a figure of fun.
Ted Nugent summed it up quite well.
I think the success of The Osbournes as a TV show is an indictment of the soullessness of mankind. Now, I'm just a guitar player, but when I see a train wreck, I don't look at it and laugh — I try to save injured people. You're not supposed to wring entertainment out of tragedy. Ozzy is a nice man, he is a kind man, he is an extremely talented man, extremely tenacious, obviously. But he is the poster boy of why I never touched poisons in my life. Because I don't want to drool, nor do I want to allow a woman in my life to take advantage of my drooling condition to make millions of dollars from people laughing at me. That's what she has done. And no one is laughing with the Osbournes — they are laughing at them. I find that soulless.
But the problem with him being in the band is that they won't play any of the vastly superior material (IMO) that they recorded post OO.
“He likes having the ball, playing football, passes. It’s like an orchestra. But it’s a silent song. But I like heavy metal more. I always want it loud.” - Jürgen Klopp