I finished the 'Purging of Kadillis' last week, and I enjoyed it greatly.
Apart from a solid storyline, the writing style felt suitable in regards to the Astartes, especially the snippet of battle you receive from an Apothecary's point of view. There's even a scene with a decent look at tactics involving Predators working together, as well as with Thunderhawk Air Support.
The Astartes aren't drastically
OTT (Which I think is becoming more of a problem in Codex Fluff than Black Library fiction now), and regret every loss appropriately. Overall, something I'd recommend looking at if you enjoy reading about Space Marines in general, or the Dark Angels in particular.