I was thoroughly hooked for the first few chapters. Jeremy, emotionally detached terrorist-turned-Sentinel, was the most interesting character to me. But then I found myself losing interest with the emergence of a convoluted love triangle/quadruple/whatever with Nick in the center. Everybody loves Nick. Young and hot musician who became one of the youngest and strongest vampires and now has two powerful and possessive vampires fighting over him. Maybe I would have been more interested if I actually liked Nick, but I just couldn't connect with him. Despite the effort to give him a tragic past, he somehow just stayed on the superficial level to me. I just found it really sad that in the end, Rory's current mate decides to stay with him knowing that Rory is only biding his time until his mate dies so then he can finally be with Nick. And that Nick decides to be with Jeremy, after also acknowledging that once Jeremy dies, he will likely be with Rory and Lorcan someday.
I seem to be the only one bothered immensely by this, so I guess I would still recommend this because the writing is decent and the world-building and concept of three races is really intriguing and amazing.