As a BDSM romance this was easily a 4.5 - 5 star read; as a mystery it was more a 3, so I split the difference. 
 I loved the buildup of Gavin and Ben's relationship - they took it slowly, discussed any doubts that came up and worked their way through them. Given that Ben is both a Dom and a psychologist, that felt "real" since both of those require lots of clear, open communication. The sex scenes (BDSM and vanilla alike) were both hot and loving. As a couple, Ben and Gavin just worked really well together. 
 The mystery started off really intriguing and held a lot of promise. As soon as we "met" the killer, though, *I* knew who did it, and since the book is written from Gavin's POV, I only had the same cues and clues he did, so for him to keep overlooking some rather obvious clues and behaviors was disappointing. (view spoiler)[He and Ben had a personal appointment with a suspect; he not only ignored warnings, he didn't even tell Ben the guy was a suspect. Even if he didn't think the guy was guilty, why not wait a few days and try to either confirm or clear the guy first? (hide spoiler)]