Here's a lesson in how different two rap acts can be. Eric B. and Rakim hip-hop along a well-traveled trail; they just move down it better than most. Eric B. (Eric Barrier) shows off his deejay legerdemain on Eric B. Never Scared, an impressive multilayered piece of aural architecture. Other songs on Follow the Leader (UNI) have good beats and uncomplicated but varied musical backings. Microphone Fiend, for example, combines a sharply picked guitar riff and sleigh bells, while To the Listeners swings to a synthesized jazz melody. The star of the show is Rakim (William Griffin). He's one of the smoothest, most syncopated rappers to emerge in the field to date. For Rakim, meaning is often subordinate to meter and rhyme. He tries too hard to fit multisyllabic words into rhymes. But he's too smooth-talking to fault. Schoolly D, the scourge of Philadelphia, takes rap down a different path—right into the gutter. He's the crudest of mean street poets, with a mouth like a torn pocket. His egregiously racist, sexist, violent and raunchy lyrics are set to implacable drum beats, blatting two-note sub-bass lines that sound like the foghorn on a garbage scow. He relaxes his guard a few times on Smoke Some Kill (RCA/Jive), with the playful This Is It (Ain't Gonna Rain) and the funk-enriched We Don't Rock, We Rap. The biggest surprise is Signifying Rapper, which marries a thudding guitar riff from Led Zeppelin to a filthy adaptation of the Negro traditional Signifying Monkey. Elsewhere on the album, he pays homage to socially conscious musician Gil Scott-Heron and the largely forgotten black activist-bank robber H. Rap Brown. In the Brown tribute, D (Jesse Weaver) raps, "If you can't understand/ It's not my fault/ It's the aggression that I feel/ You can look in my eyes/ And see it's for real." This is clearly not a casual listen. Most of the time Schoolly is pretty forbidding, though his grim style carries an insidious vitality and candor. Rap fans, choose your poison.