There were some bands that were going in a heavier direction at the time, but to say that any incarnation of Sabbath other than the Ozzy fronted version is better than the original is just false.
Hold on now, that's strictly a matter of opinion.
They did some groundbreaking stuff, and
along with a couple other bands of the same era essentially pioneered heavy metal music, but let's not overstate the matter here. A good portion of it was being in the right place, at the right time.
The stuff the band did with Dio and Gillan singing was much better than a lot of the Ozzy-era stuff, and it could just as easily have been either of them in Ozzy's place. I know, it wasn't, and who knows how things might have turned out had it been either of the other two.
I suppose there are two ways to look at the question presented here: the musical aspect, and the effect on music history angle. You'd be hard pressed to make a case for either of the other iterations in favor of the Ozzy era if we're talking strictly about the latter.
However, looking back and taking the songs on musical merits alone, I find the music produced during the Dio and Gillan eras head and shoulders above (much of) the music of the Ozzy era. Plus, the whole actually being able to sing aspect and all that.
To say that someone's opinion is "false," however, is taking things a little far, I think.
