Mini-review: The Siege of Castellax

I just went through C. L. Werner's The Siege of Castellax.  It's a "Space Marine Battles Novel", though that's a bit of a stretch as the only Space Marines involved are of the traitor variety.   The basic plot is that the Iron Warriors-held world of Castellax is invaded by a horde of orks.  Mayhem ensues.  Orks and Iron Warriors, how could I resist?  I went through it pretty quickly, and