Ive just put down "Soul Hunter" by Aaron Dembski-Bowden which is a nicely done book on the Night Lords Traitor Marine Chapter. I was almost hesitant to start reading it because i thought it would be too full of hack slay chaos blah blah blah. Well written with a mix of Heresy era background and present day (40K) writing this book was a relief after a handful of Black Library books that seemed to be loyalist propaganda rather than good stories.
From the smattering of "void" battle and ship boarding actions and characters that seemed very real with their conflicting natures to the revelation of the poor state of the Chapters resources this book seemed to be thoroughly thought out and written as a novel rather than a cookie cutter Chaos manuscript.
I'll have to watch out for "The First Heretic" which is coming in November.