Being as this is book 2 in a series, I'm not going to focus too much on the author and shifter/gay relationships because if you're reading book 2 before book 1, that’s your problem.

This is a great second book in that it's consistent in tone and expands the world further, as well as giving us a new relationship dynamic and new/expanded characters to love. We get to see more of Tank and the other members of the pack and their integration into the shifter and human communities in San Francisco. Sassy and observant, with characters who don't do stupid things for the sake of moving the plot forward; a Gail Carriger standard.
This book focuses more on werewolf identity and pack dynamics, and a relationship between 2 rarely seen characters in romance (at least for me): a large (and very empathetic) man living in fear of his freedom being taken away, and a large man struggling with his identity/place in life.

So that I can clarify further, here is a tiny KINDA-SPOILER that I feel might affect your enjoyment of the book, (if you missed the subtle hints in the blurb like me): the core relationship is DS, i,e, dominant-submissive. This may be quite uncomfortable/arousing for different readers and it's not a dynamic I love, but I've read it before so I didn't get too distracted by it.
Also, if you know what A/B/O is, no, this book has nothing to do with that, despite the name.

In terms of their relationship, I think it relies a little more heavily on shifter lore (understandably), and as usual, escalates (sexually) relatively quickly. However I think the DS aspect doesn't overshadow their emotional relationship in the least, and their independent emotional resolutions have little to do with their dynamic or even their relationship with each other.

If you like Gail Carriger's writing you'll like this, if you like mild DS and urban werewolves, you'll love this, if you like relationships between emotion-whisperers and their solid rock, you'll probably love this.