I got into this series with the "internal quartet" beginning with Seeing a Large Cat, and it's always been the family dynamics, much more than the actual mysteries, that I care about.
After I finished off those four (because I was desperate to make sure it all ended well), I went back to the beginning and am now reading the others in order. The first few were entertaining enough, but in this installment I really felt the emotional dynamics that had gotten me hooked. Amelia's inner strength and devotion to her husband are put to the test in deeper ways than ever before (when it was merely their lives that were in danger). And Ramses is even funnier in his letters from England than he is in person.
My only complaint is that this is the only book so far where I actually guessed who the villain was. And, while nobody's claiming these books are realistic, this particular twist was beyond implausible. Still, this was the first time since I finished off He Shall Thunder in the Sky that I wanted to start the next book immediately after turning the last page.