Let me explain that by saying KotBR is a great novel. It gives us what its predecessor, Vampire of the Mists, didn't have: blood and gore galore, which is essential to a good action novel. The story of Lord Soth's journey from the burned-out shell of Dargaard Keep to his own domain of Sithicus is a compelling one, and very well-executed.
What I don't get is why so many people harp over the fact that he went. Yes, the vast majority of them are DL fans (like me), who believe RL "stole" Soth and that he belongs in DL. He did, but after the conclusion of Test of the Twins (presented from his point of view in this book's prologue), his usefulness on Krynn had ceased. What to do with an excellent character? Bring on the Mists!
The fact that this book was mostly action, consisting mainly of a death knight running around in Barovia and Gundarak and slaughtering whatever he came across, is what makes it only 4-stars. It had some story, some character development, and it had Strahd (in a version I much prefer to the one in VotM), which makes it more than passe. If Soth and Strahd were the only characters, the book would have been poor indeed. But, we also got Caradoc, Magda, and Azrael, as well as the only novelized appearance of the late Duke Gundar and his dhampir son (whose name escapes me).
Anyway, the book was good enough to truly draw my attention to RL and make we slaver in desire over the upcoming sequel, Spectre of the Black Rose, which is supposed to settle all the disagreements between DL and RL over Soth. I know it won't, as he has to end up in one or the other, and the other side will be unhappy no matter where he ends up. Oh well, c'est la vie.