I finished Faith and Fire by James Swallow a few days ago.

Set in the same Warhammer 40K universe as this book,  Faith and Fire is better written.  The action scenes are clearer, the characters are better written and the plot fits together more easily. 

These novels all have to walk a fine line, since the side of evil is over the top evil while the side of good is a fascist, oppressive and grotesque theocracy.  The obvious way to maneuver around this is to have one of the powerful good characters turn out to be the real villain.  I guess that could be considered a spoiler, but only if you weren't paying attention, since the suspicious nature of this character is obvious from the start.

Overall, a decent novel, but one that only caters to a very specialized taste.