2 prefacing points: 1) I am a fan of Gail Carrier from her original parasol protectorate series, I haven't read the rest of the series in that universe yet and I'm aware that this book/series is set in modern times and is not technically connected to said universe (to paraphrase her blog, 'it could be').
2) you have been warned that there are erotic gay scenes in this book, if you don't want to deal with smut, go read the parasol protectorate, and if you don't want to read gay, PISS OFF.

Now, I binged this in 1 go and loved it but felt it was missing something. Upon further consideration I realised I was expecting a dramatic showdown a la most of the parasol protectorate books. This isn't a book about saving the world or even San Francisco, its about 2 people who fit each other really well, and how they (or rather, mainly Max) deal with the effect that has on their lives and their expectations of themselves. In that sense it's a true romance novel.
As with most shifter (and gay) stories that I've read (admittedly not extensive so I may be biased), the relationship escalates relatively quickly, and Ms. Carriger doesn't disappoint in her writing. She also sets up a whole new world and its rules seamlessly, without any stopping of the plot to describe elf lineages, Tolkien I'm looking at you.
Fans of her historical fiction will be a little disappointed if they expect the same attention to fashion and food, but the witty repartee is still in form and the proliferation of likeable or at least interesting side characters. If you haven't read her Marine Biology short story, it’s not really necessary, the origins of the pack are briefly and not intrusively explained, but I personally think you'll get a better feel for the Alpha couple and Biff/Bryan if you read it. (it's on her website)
If you love werewolves and urban fantasy, I think you'll like this, if you want smut with plot you'll probably love this, and if you love sassy insecure guy meets caring quiet guy, you'll definitely love this. Just don't expect a big dramatic climax or life-endangering stakes.