Easily the superior of the three. Certainly not for everyone, but I can't agree with Malus Darkblade: I've read a lot of tedious action scenes in 40k books, this book had not even one of them; the Chapter were more interesting than most others I've read; the world was delightfully imagined, far from boring.
Compare the action scenes between Helsreach and LotD. Each battle in Helsreach felt new and exciting while in LotD , it just consisted of ten chaos Astartes dying to one loyalist, crazy civilians dying to mass las-fire or scouts getting bitten in half by daemons and not realizing it for several minutes.
We have a World Eater who fought with Angron and was at the Siege of Terra get his throat slit by a ghost, even the author pokes fun of how stupid that scene was. And I don't want to get into how cliched and stereotyped the WE's in this book were. One of them destroys the circuity of his drop-pod before it lands because he's mad
The Exco. chapter just have slaves whip them while they moan about the greatness of Dorn. Not my cup of tea. And the feast of blades was just silly. Give each contestant a poisoned knife that can paralyze half your body with one touch?
To me that's not a good way to gauge one's strength or skill at all. The feast of blades should consist of heroic battles that last forever until every sinew and bone in the contestant's bodies is pushed to exhaustion. Dorn is all about persistence and preserverance. I am not even going to talk about the He-Man who threw a pillar around and how dirty the protagonist was for holding a Black Templar in place as said pillar flew into his face. Why did he even need to do that? To take out one contestant? Ok but wow that was dirty lol (in b4 exco's are attrition fighters, etc).
And the psychotic obsession with a banner. Fine ok it's a relic given to them by Dorn supposedly (if I recall correctly. If so, you would think they'd lock it up in stasis) but for them to hate the protagonist for losing it in an ambush
is just silly and unrealistic.
Call me naive or what have you but yes I was expecting a book about the LoTD. I had no reason to assume otherwise. Prior to reading the book, I actually thought they were a flesh and blood chapter (curse you lexicanum, curse you), damned by the warp but serving the Emperor before their bodies were completely lost to Chaos. That's cool. Not ghosts who just slit throats and fire magical bolters. They were used as bait for people to buy the book.
Writing was solid but I just had issues with all the above.