I recently had the opportunity to listen to all 4 Mastodon albums in order on a long car journey and it made for interesting listening. You can hear the bands sound evolving. The first album is raw in your face metal, interesting but not for the squeemish. By the time you get to this album the sound has become more commercial (For want of a better word). That is not to say it is commercial, this is not the Black album and won't appeal to non fans of heavy music. And that is not a bad thing, this is still very much Mastodon. It takes a few more listens to get into this album than the previous albums, but it is definitely worth the effort. It is an excellent album but I can't see it breaking them into the really big time, but that's fine they have managed to evolve without sacrificing that essential Mastodon sound. Recommended!!