One thing I will say about this book is that it's Dickensian--but not in a good way. In a lot of Dickens' novels, there are tons of amazing coincidences and things just falling into place and making everything shiny so that the hero and/or heroine can have a happy ending. There was a lot of that at the end of the book. It was remarkable how Yelena's plan to save the day all comes together with just a few words to her friends. A lot of that master plan happens off-stage, as it were, and very quickly. So quickly, it's rather unbelievable. The last fifty pages or so felt really rushed.
After I read the ending, I wonder if Snyder is going to write more books in this series. The news from Snyder's website tells me that she plans a new series--set in the same world--but featuring different characters.