These guys are very popular, their song Junk from first album (yes, it's about a heroin and lyrics are "What i know about junk! Just funk! Junk is me and me is junk) knows whole teenagers.
They started as usual rap-core band like Limp Bizkit with their album Pull Ya Let It Doll Go, with simple music and social lyrics about junkies, pimps and dealers.
On second album, self-titled one, you can listen influence of Deftones - music got slower and more heavy, lyrics became more sensible.
Third album, Père Lachaise had published in the times of Emo-Boom so they couldn't do something in The Used way, so - songs only about love, kills and suicide and usual emo-core music.
Last album, Sex and Violence is a normal rock-album, nothing special except lyrics influenced by Stevenson's book (Jackil and Hide) and trash-movies (Geisha Ninja Killers)