Though they've been dogged by incessant comparisons to Mastodon (who they shared a split 7" with back in 2003), it's more a case of American Heritage having an extremely similiar set of genes as their Atlanta brethren. That set of genes, of course, being a shared love of dizzying prog/math rock complexity welded to gymnastic thrash metal and pinball shredding topped off with a big ol' heaping of Sabbathy heaviness. That said, there is no denying that Mastodon fanatics in particular are going to love American Heritage and their brand of technical, jagged progthrash. The seven songs on their fifth album Millenarian make up a freakin' feast of intricate arpeggiated riffing, wicked time signature changes, haunting melodic guitar parts that creep out from under the angular riffs, and more straightforward thrash metal shredding, formed into complex arrangements that frequently tend to lose the gruff, powerful shouting vocals and veer off into purely instrumental territory. Their early stuff like 1999's Why Everyone Gets Cancer was entirely instrumental, but I dig the occasional blast of vocals that the band use now, it adds a serious punch whenever they show up over the convoluted, chunky, twisting riffage. Sure, the Heritage know when to pull back and ride some monstrous grooving riff or slow it down to a crunchy, jackhammer breakdown at opportune moments, and there are some fucking skullflattening parts on here that remind me of Coalesce, which make this more than just some techy math-metal workout. The riffs are massive though, and they come at you relentlessly, changing shape every few seconds as the drummer lays down an amorphous rhythmic assault. Definitely one of the most underrated and overlooked bands in the metal underground, this disc needs to be heard by fans of everyone from Knut to Kylesa to Dazzling Killmen and yes, Mastodon.