Illumination Undone is one of my favorite albums, although I'm biased because they Empyrean Eclipse is from my hometown. Unlike so many American bands, their brand of melodic death metal is something that can definitely compete with the Scandinavian scene. This album gave me hope for the future of American melodic death metal.
Their style is a mix of melodic death metal and melodic black metal that is aggressive mostly while also being very beautiful at times. I would say that their style is something like a mix of Dawn and Hypocrisy--something close to Withered. They play all of their instruments pretty precisely and have really great riffs for headbanging. As I got into metal through melodic death metal, I have heard a lot of generic bands in that genre but Empyrean Eclipse really has their own sound that is extremely refreshing.
The only downfall of the album is the vocals. Marty's vocals are excellent on the low end but his high voice is slightly annoying. But they only detract from the album slightly.