I have been a Slayer fan before Reign in Blood broke all the rules regarding thrash, ferocity, and brutality. South of Heaven and Seasons in the Abyss remain masterpieces, worthy of continued praise. Than along comes Diabolus in Musica! Many "so called" die-hard Slayer fans complained the band comprised its roots by aiming this disc towards nu-metal fans. A veteran band like Slayer can't re-cycle music that shows a regression in ability. They needed to re-invent themselves, while not alienating thier fan base. Diabolus is Slayer! Powerfull, heavy as hell, brutal, and dare I say, they have incorporated some "groove". They have not comprised any of the savage approach that has made them the KINGS of metal. Standouts include: Bitter Piece, Stain of Mind, and Scrum. Is this their best album, I don't know, the album just kicks ASS!