Unfortunately I'm the wrong person to ask which era ( Ozzy or Dio) of Sabbath I like the best. I LOVE BOTH! Probably the ONLY band in the history of popular music where two back-to-back incarnations of a lineup produce high quality of music on equal levels! So I guess I'll skip the vote.
That said, I'd rather hear Dio-era Sabbath over Ozzy AND Dio as solo artists any day of the week! No contest!