Halfway through Darkness in the Blood. Both Dante and Devestation of Baal were really good. Dante being written as an /r9k/ sadboy is pretty funny. I wish Devastation included more Primaris stuff. Shit take, I know, but if you're going to introduce an entire brand new, meta-changing "thing" like Primaris, and make most of DitB about the Rubicon, then Id at least like to see Guilliman clapping Tyranid cheeks with the Unnamed Sons. Maybe a chapter dedicated to a new Primaris Blood Angel and how he feels prior to and during his transition from Unnamed Son to Son of Sanguinius. The history, the legacy, all of that could've been very cool. Primaris were also in cold storage for 8k years, so maybe something about how Sanguinius and the other Primarchs were seen then, versus how they're seen now couldve been interesting, even if its just fragments of a childhood being taught about Primarchs less as saints and more as real, living (trans)humans.
The black rage also being touched on wouldve made DitB better (so far at least). A new Primaris marine feeling something that he cant explain, that he doesnt want to try and explain, thats implied to be the Black Rage/Red Thirst would make them feel more real. After all, how would the Blood Angel-based Primaris even know what the Black Rage and Red thirst even IS if its such a closely guarded secret of the BA?