My favourite recent totally "underground" acid techno tune !

[Aratron]

I can see clearly that the godfathers were ozzy and alice cooper to name a few, I still wouldn't put them above Slayer.

Black Sabbath are a much better band than Slayer.

[AcidTrash]

Black Sabbath are a much better band than Slayer.

Black Sabbath almost certainly influenced Slayer but that does not mean that Slayer did not run with it and produce something entirely different, a sub genre in itself. Which is better is entirely a matter of taste.