I ordered the Kindle edition of this book, though I read it on my laptop, not on a Kindle. Since many readers have reported problems with Kindle editions of books, I feel the need to report that I thought this was a fine edition - no missing pages, all the content there, not buggy, etc. So, just for the record.
Now to the story. This is a great story. Other reviewers have said things like "the prose sparkles" (it does) and "the characters are three dimensional to the point that they leap off the page" (they do). It's a fantastic world she's created, and as a person who really enjoys gritty pseudo fantasy/scifi settings, this one is top-notch. I personally also really enjoy carnival and circus atmospheres, so this is great.
Valentine also plays with the theme of circus life and performance having a magical or shamanic element to it. Death and rebirth, and a power tying all of the circus performers inexorably together are major themes. As a student of anthropology, I ate it up.
I also like that she doesn't reveal too much about this world or the characters. The characters have all taken new names, and "what their names were before isn't important". The ringleader of the circus is simply Boss, for example, and the relationships between the characters are very skillfully and subtly defined. Well done.
However, this good point is also an aspect of the book that I find a little annoying. A little. It takes a very long time for what is actually happening to come into the open, and there are lots of interruptions along the way to flash back and reveal something about a character's past or something. Stylistically this is fine and interesting, but at times it made me frustrated to just figure out what the heck was happening already! Still, those moments were few and far between, and I got through them easily enough.
Also, there are (I think) two voices, and at times I have trouble telling them apart. One seems to be a nameless narrator, and the other one of the named characters, but there is no real difference in the cadence of their voices, so sometimes that's just a bit jarring. Still, I enjoyed the voice very much, and perhaps it is indeed meant to be the same voice anyway.
One reviewer commented that they found her prose style a little complicated - heavy use of parentheses, for example. This doesn't particularly bother me. I suppose I could see how it might bother someone, but I think it's done to create an effect, and well done at that.
So, all in all, 4 stars.