I thought this book did some very important things for the characters, Gideon and Eva. Namely, it showed them really learning to trust each other. This is one of those "extreme romances" where both are totally messed up, obsessive, selfish, and immature, but somehow, through Sylvia Day's writing, you want "those crazy kids" to work it out. So, it doesn't bother me in the least that the books went from three to five. We know they'll get there and they still have a ways to go. (Eva, I'm looking at you. Ahem.)
The sexytimes are ridiculously hot. So, so hot. They are not filler, but advance the emotional connection between Eva and Gideon. Did I mention that they were steamy? Lawd.
My favorite parts were the ones showing E and G together and happy. They laughed, they cuddled, they de-escalated stupid shit that would have caused major problems in previous books. There were lots of those scenes and they were awesome and needed. (It is a pet peeve of mine when a romance ends and we're given like 2 pages of actual happiness.) There were so many sweet scenes of them together, comforting each other, talking out problems. Very well done.
Gideon had stalker moments, which I don't approve of, but he was working on being less of a possessive neanderthal. I'm still not sure how he ever gets any work done, but whatevs. I did appreciate being able to see him as more of a 28 y/o and there were several scenes where he seemed more like his age. I really connected to that in this book.
Eva still seems to prefer to help others with their (love) lives rather than just live her own. For instance, letting her mother dictate whether she'll live with Gideon. There are times I don't find her particularly likable either. But, again, I don't think she's meant to be. She has a kind heart, but a serious case of an inability to say no. So, we'll see where she gets in two books.
I still really enjoy the series. Sylvia Day is an amazing and wonderful writer. I highly recommend this series.