There are some very charming moments in this story. The interactions between Marco and Katie are tender and the dialogue is sweet. I admired Katie's courage of reaching out to Marco via Craig's List. Truly, a contemporary twist to finding a missing connect. I can also admire a guy who drops everything to meet a girl for the possibility of something. Those are the reasons we read romance, right? Beyond that, this is a very familiar story that does not add anything new to the traditional trope.
I do have a critique of the title. "The Viper" seems to imply something that the book is about a fighter. Unfortunately, this book has very little to do with moniker. There is hardly any fighting and little about the world of MMA fighters. Given the context of the her previous series, Battered Hearts, it would be very easy to assume that this would too. Readers need to know this is NOT about the fighting world.
IN A NUTSHELL:
Readable and enjoyable, though not terribly original, I would recommend this book if you are interested in an sweet romance not in the context of the fighting ring.