I really don't know where I stand on this book, and from takes other friends have had it seems they had the same experience. Of note, without knowing anything about the story, there's a certain usage of pronouns that tossed my brain for a loop. This eventually sorted itself out for me, but the opening chapters or so lose themselves in flashbacks and introspection and it's vague how important specific characters are. Without having any clue what was going on (no specific actions to tie myself to) I wasn't sure what was important and was quickly losing interest in the story. Although, as more flashbacks came I stuck it through and found myself interested in those until they reached their conclusion. This is about when I wager the story begins to make sense for most folks, including me. Of course, this is about halfway through the book.
So much of the story is about the human condition. Among the primary themes are slavery, emotion, society, and gender. The Radch are an interesting group of people who express themselves genderlessly and yet wear all of their feelings on their sleeves. Who live in a complete absence of privacy, yet keep ancillaries in stasis. They run amok across the universe annexing planets and people calling themselves civilized, yet can't see or rather ignore that their Lord keeps them under her thumb. Information is more important than the people who live there, but people still make decisions based on that information. In truth it feels nihilistic as opposed to my first view of it as dystopic, yet religion abounds and from the multitude of religions comes individuality.
The other of half of the book was much more interesting. There's a set of events in the flashbacks that drive suspense and you keep waiting for the 'omens to fall'. When they finally do, it's very satisfying and it sets up the next book quite well. While I was left with more questions primarily about the future of the protagonist, for most of the book it never felt like there would be a future. I found myself wanting to know more. As for this story, I think you'll have to try it for yourself and see whether you love it or hate it.
Another more in-depth review can be found here.