This was a decent suspense/thriller romance, if a bit predictable. I really like the different way they explain shifters (and vampires, etc.). It's not positive, though, so beware. I do look forward to reading more.
The thriller aspect was quite good, the story unusual. The sex was good. I liked the characters even though they weren't particularly original.
A few nitpicks:
The men were in a constant state of arousal around each other to the point that I felt it was all lust. I had trouble buying the deeper emotions until the end.
One guy licks a guy's six-pack abs and it's described as, "Letting his tongue trace each 'pack,'..." It's a pack of six. Not six packs.
Near the climax when one guy is terrified the other is in major trouble, admitting to himself that he really cares about the guy, maybe love, we get:
"He'd never been so stupid about a piece of ass before."
Yes, touching and romantic. For this reason I'm rounding down from 3.5 stars to 3.