The actual
material was better with Ozzy at the helm, but Dio was a much better singer, and one of the best rock/metal vocalists ever.
And why is this in the Political section?

I agree with this.
Most of the Black Sabbath albums w/ Ozzy were pretty damn good except for the piece of garbage that was 'Never Say Die'.
Dio had some good ones with Sabbath but also a lot of crap.