It's an excellent book, a tremendously deft and assured book, but I never had that moment of my socks flying off my feet as the world moved. But again, I had more to think about, during and after, than any other recent read has offered me. That's worth a high rating all by itself.
(I consider the possibility that I spoiled my reading experience by reading too many reviews first. Usually I avoid that sort of thing; I am spoiler-sensitive. But the question is un-investigatable, so I'll set it aside.)
I'm not going to summarize the setup or plot; all the other reviews have done that. Instead I will talk about the protagonist.
The fun of this book, the fun I had -- again, leaving aside the fun of figuring out the setting, which I basically missed out -- was figuring out what the protagonist is.
Early on, I said "The narrator is not human." She (I'll also skip the pronoun discussion) describes events that she participated in, but with a sense of utter disinterest. She describes the horrific Radch civilization -- brainwashing, genocide, god-emperor autocracy -- with complete complacency. So I think, right, she is a computer. Her sense of human emotion is a medical data stream of hormone levels. She says "Awn was frightened" but has no human understanding of what that means.
Then, as the book runs on, we can see a trickle of what the narrator isn't telling us about herself. She has responses, involuntary reactions, which are only mentioned in retrospect or in implication. So I think, no, it's that style of unreliable tight-focus narration where you have to dig. The sort where our hero looks down after a conversation and sees that he's smashed his hand into the wall until it bled. (Not an example from this book, but you know the sort.) In that mode, the narrator is all sorts of human -- if perhaps not my sort -- but refuses to admit it.
Then the book gives us scenes where the narrator -- who is unquestionably a computer, on the literal level, no matter what else she is -- is being programmed. She has involuntary responses, beliefs, memories or memory lapses, which have been manipulated in obvious ways. Some of them are obvious to her, but there's no guarantee that's always the case.
So now the strategy of unreliable narration as character-building has been undercut, or mixed, with unreliable narration as a simple fact of the story. The character is divided against herself as a narrative theme, but also actually divided against herself. And the balance of these elements in the story is where I say, okay, the author is pulling off a serious stunt here.
Then, even further, we realize that this division-against-oneself is not an element of the story; it is the entire story. The Lord of the Radch is divided in exactly the ways that the protagonist is: by programming, by refusal to communicate, by the impossibility of reconciling with the self, by guilt, by the inability to perceive love. As the Lord of the Radch, so the Radch entire -- by definition. This series is about a civil war of a galactic empire, and the civil war is the same as the protagonist's struggle to exist and to tell us her story.
This is where I say, okay, I see why this book has awards raining down on it.