It's easy to knock Slipknot for its silly rubber masks, but at least the nine-piece Iowa metal band does its thing without resorting to the angst-ridden whining that pervades the million new-metal soundalikes surrounding it. That pseudo-scary half-spoken/half-sung/all-lame delivery has become for metal what pompous, Creed-style bleating has become to alt-rock: a joke. Not that Slipknot doesn't tread about a thousand miles of familiar ground on its ornately packaged, epic-length album Iowa. "I wanna slit your throat and fuck the wound," Corey Taylor roars on "Disasterpiece." "I wanna push my face in and feel the swoon." Iowa doesn't get much subtler than that, as Slipknot sticks to a bludgeoning, unrelentingly mean-spirited constant from start to finish. It's almost enough to inspire a strange sort of respect for the group's single-mindedness: This stuff is so joyless, severe, ugly, and hateful that it seems to represent an actual philosophy that exists outside of trends. Slipknot's status as a multi-platinum hit-maker does diminish Iowa's effect—it's hard to think of the band as anything but GWAR after a humorectomy—but the album's seething grindcore stomp will probably scare mom and dad with or without visual accompaniment. Those who've moved beyond efforts to scare mom and dad will do well to steer clear, though they've probably made that choice already. The legendary Slayer shares Slipknot's dogged fury and persistence of vision, but God Hates Us All clearly illustrates why it stands a good chance of outlasting its Iowa brethren. For starters, Slayer doesn't add any window dressing to its bile-filled Satanic metal. Instead, it just relies on its three core ingredients (speed, power, and precision), and as a result, its music is not only blisteringly potent, but also sort of fun. When Tom Araya shouts, "I keep the Bible in a pool of blood so that none of its lies can affect me," the line is funny, whether intentionally or not. As it approaches its 20th anniversary, Slayer doesn't have anything new to say on God Hates Us All, and doesn't pursue any new ways to say it, but considering the trendy paths the band could have followed, that stasis feels like something of a noble gesture. If Slipknot's nihilistic vision is this ideologically and sonically pure in 19 years, it'd be the group's biggest shock of all.