It's really difficult to review this without spoilers.
So, let me say this - There seems to be a tendency in books to make an unlikable narrator, but usually the book falls apart. This does not happen here. There are parts of the book where the eye brow goes up, but it is a good compelling read.
What I really liked was the reveal. That was good, even though you could somewhat see it coming. But Hamilton seemed to know readers would be able to call it, so she makes it work.