I'll admit. I wasn't always the biggest Dio fan. I still prefer the Ozzy years of Black Sabbath, but that's because I like the sludgy heavy sounds, not because I think Ozzy is a better singer (he certainly wasn't a better lyric writer, "the devil is bad, war is bad, do drugs yeahhhh").
But I did always like those first couple solo album, and still do, and I've come to terms with the two Black Sabbath albums he did. "Come to terms with" sounds weak. I spin Heaven and Hell and The Mob Rules a LOT. It should be easy to see for any metal fan that they reinvented themselves for the 80s successfully when the heavy metal world was starting to pass them by. And Dio had a huge part in that. Sadly, I never got to see their reunion as Heaven And Hell.
At any rate, there were few sets of pipes as amazing as Dio's. RIP, here's one last set of horns for you: \m/