Nyx is a protagonist who could've easily failed. A world-weary warrior, devastatingly competent, despised by most, and yet possessed of a certain soft side - it's been done before. Hurley pulls it off, in part by intelligently showing the effect that Nyx has on those around her. God's War is a good novel with unique, bugged out world-building, tense action, and some memorable characters. Infidel is a great novel, depicting the harrowing reunion of Nyx with her old crew, delivering more visceral violence, and asking some almost unanswerable ethical questions. Rapture is less effective than its two predecessors. Hurley has confessed that plotting is a weakness, but this is most apparent in Rapture, which sees Nyx extorted out of retirement to bring in another bounty.
The world-building has always been part of the appeal for me. Umayma, with its hostile environments, diversely grotesque insects, and constant warfare, is fascinating. Hurley has been accused of accidentally racist cultural appropriation, but I see her depiction of a centuries-long holy war between quasi-Muslims as being critical of religion in general, instead of targeting one group. As further revealed in Rapture, some nations in Umayma seem more Christian in nature, yet are just as dysfunctional. And the religious don't have a monopoly on violence - Nyx, an atheist, kills as much as anyone. Anyway, the world-building continues to shine in Rapture. As Nyx travels north, we gain access to the bizarre edges of Umayma, where blood-eating sand dominates the landscape and local potentates ride ant-driven chariots. We learn more about Umayma's history, and why it's turned out so bizarre. Wisely, Hurley continues to be economical in her approach to world-building, refusing to infodump and/or answer every question.
As previously mentioned, Rapture's plot is far from perfect. Nyx, living peacefully out in the Middle of Nowhere, is called out of retirement to track down an old employer/enemy. Her home country, Nasheen, is set to implode, now that the seemingly everlasting war is over. Personally, I'm somewhat wary of travelogues, and a large chunk of the book involves Nyx and crew trekking northward. As a character, Nyx is as good as ever, but it feels a bit as if we're treading over old ground. The handling of her relationships with others isn't really different from what we had in Infidel, where the interpersonal drama was more compelling. In particular, the handling of Nyx/Rhys will they/won't they is a little too familiar. Like in the previous books, the plot's resolution involves the revelation of political conspiracy. The problem is that we spend most of the book on a standard adventure, and when the plot winds down, all the intrigue is thrown at us in incomplete infodumps. The situation in Nasheen, bubbling on the verge of chaos with the war over and the vets home, should've been explored in greater detail throughout the novel.
Then we have Inaya, who's journeyed from meek self-loathing girl to confident, over-powered woman leading a shape-shifter's rebellion. In Rapture, there's a period where her story seems a little stagnant. She's stuck in one place, and Hurley doesn't give her anything terribly interesting to do. Inaya wants her rebellion to focus on peaceful tactics, and her enemies within the organization want to resort to violence. This is a conflict with potential, but many of Inaya's chapters are spent away from it.
Some will inevitably complain about the book's final pages, but I rather liked them. The end seemed appropriate in light of everything that had transpired. Ultimately, Rapture is an enjoyable book which continues the tradition of its predecessors. There's conflicted anti-heroes, unique world-building, politics, religion, and mystery. It's too bad that the plot is less inventive and less exciting than in God's War and Infidel, but Rapture is still a good book. Hurley's fans will enjoy it.