The Emperors legion novel is definitely worth a read.
How are the others 'new fluff' books (I am pretty late to the party, just beggining the Eisenhorn thing !) ? Have you enjoyed DI ?īy and large they're not bad, (I thought DI was actually the best post GS novel), even the 'Advertisement' bit of DI isn't that bad when you realize the context of the books release, it came out when the DI boxed set was new, so we didn't know anything about primaris marines, save what was in the DI box and the index, so this was the first bit of fleshing out Primaris Marines gave us, I remember reading the book at the time and picking through it to get an idea as to what was coming. I am looking forward reading the next book about the Plagues Wars ! the scene featuring primaris marines are just advertisement, like, it is not even hidden or subtle. He was handled better than I thought he would be.
Even Guilliman is well written and, even if I still despise his stupid resurrection, I enjoyed reading the parts about him, and his insights. So I have just read the Dark Imperium book, and, eventually, it is was pretty good one to my humble opinion.