It's really quite a funny show. Brendan Small is the creator, and he was also the guy who worked on Home Movies. I had no idea he was a metalhead, but apparently he lives for the stuff and actually graduated from a music school. He just decided to go into comedy instead. His goal was to have a funny show and make fun of metal while simultaneously paying homage to it, and it's surprising how well he pulled that off. It's totally stupid and funny, and it makes fun of all kinds of metal stereotypes, but then it guest stars the voices of all kinds of musicians (Jeff Loomis of Nevermore, my favorite guitarist, was also in there), and the guy goes out of his way to write music that he thinks is actually good, even if the lyrics are really silly.
But yeah, it's surprisingly good. I wasn't sure if I'd like it at first, but thus far I have been thoroughly entertained.
I read an interesting bit the other day that said Small took all of the artists to a Behemoth concert when telling them what he wanted the show to look like.