Haunting at times, brooding and dark, is how I would describe the music here.
The music from the original game was released on the developers page soon after its release and those from the expansions were previously available in the form of unofficial soundtrack compilations floating around the internet but now the music from the Dawn of War 2 game and its two expansions is finally officially available and combined into one package for your listening pleasure.
Doyle W Donehoo may not be well known (he wasn't to me before) but in my opinion he's done a marvellous job here. There is a good selection here, including the haunting themes of the Eldar, the brooding insidiousness of the Tyranids, as well as themes for the new races Chaos and Imperial Guard and the music combines orchestral motifs with choral accompaniment interspersed it captures the dark, grim setting of the Warhammer 40k universe well.
I should point out that this will not sound like the music from the game, because the in-game music is split into different channels which are intermixed to give different effects but nevertheless, if you're a fan of the music from the Dawn of War 2 games you will enjoy this a lot, like I do.