There are two things I bothered me about this book. There are too many POVs. I don't think Grace and Laila really needed things told from their POV. I really think that the story would've been better if their story was told from someone else's POV. Second, there are some aspects to the ending, or really one part in particular that I didn't like. Other than those two things, I think it was a fairly good story, but not as good as I would expect after reading the first three books.
Here's the thing that gets me, why did Grace have Soren's baby? Why did Soren give in and have sex with her? She is not the first person who would've "sold their sole" to have one night with him. Did he somehow know that the reason Grace and Zach hadn't had a child yet was more on Zach and Grace and wanted to give them the child they wanted? That would be something I could see Soren doing. I don't see him having sex with anyone besides King or Nora for any other reason.
I will say that I was very happy for Wes, I think Laila is the right/better girl for him. It is also good for Laila, because I do think that Soren was going to prevent her from ever having sex if he could.