Rumor has it, Ancillary Justice won a lot of awards when it came out a few years ago. This is fair enough, because it ties a well-written take on an intriguing sfnal concept (that would be a spoiler for the early book to reveal, see footnote  below cut) to a good story that, to nobody’s surprise who has read the title, is deeply concerned with justice on both personal and imperial scales, and it wraps that package up in meaningful social commentary on the topic of gender and identity.
I should probably read the other two? I’m not sure how much they will further address cool sfnal concepts and meaningful social commentary, but like I said: the story was good too. Problematically, I own neither.