The world-building is great. It is like Brandon Sanderson. Things that happened hundreds and thousands of years ago led to the strange world we see today. Gradually uncovering the secrets of the distant past really drew me in. No way I could stop after the first book.

It has an excellent structure too. Chapters from the lives of three main characters (Damaya, Syenite, Essun) are interlaced. (Do not read spoiler if you plan to read the book: They are really three parts of one woman's life. Felt great when I figured that out!)

It has a unique style. All present tense and one of the characters is in second person. By the third book I have entirely gotten used to it, but it felt out of place at first. The style is also intentionally loose at times:

But you need context. Let’s try the ending again. Writ continentally.
Here is a land.
It is ordinary, as lands go. Mountains and plateaus and canyons and river deltas, the usual. Ordinary, except for its size and its dynamism. It moves a lot, this land. Like an old man lying restlessly abed it heaves and sighs, puckers and farts, yawns and swallows. Naturally this land’s people have named it the Stillness. It is a land of quiet and bitter irony.

Three books in, I have not found a reason for this style. We eventually learn that the narrator is one of the characters. But he has no reason for this style. The intention may be to distance it from typical fantasy. To me it more often felt like trying to be edgy.

There is a lot of violence against children. Up to torture and murder. While it certainly has an emotional effect, I think I would have been fine with a little less. The whole atmosphere is very depressing. All the characters are broken beyond redemption. (Or dead.) This makes it a harder read than necessary. I'm sure this is intentional, and I admit it's interesting.

It's one of the best combinations of sci-fi and fantasy. If you like it, try Caves of Qud!