Ozzy I guess. I would pick Dio since he’s actually been a great front-man in more than one band. Outside of Sabbath, Ozzy was just a solo artist with a bunch of different backing musicians and studio artists. I’m partial to bands.
That and Ozzy always sounds whiny to me.
But in the end, I really like the sound of Led Clones and I didn’t have to hear Ozzy for the rest of that album.