Although Serpent's Kiss is not as fantastic as Dragon Bound it's miles better than Storm's Heart.
I've already mentioned that my biggest problem with the previous book was lack of spark between the couple. Tiago's character and constant moodiness didn't help.
Rune and Carling on the other hand suit each other very well. They are both cool, collected and full of inner wisdom. Rune is also sexy as hell. Carling as an ancient Egyptian vampire queen goes through some absolutely unexpected transformations while she is slowly getting back her will to live.
The plot twist with time travel and its implications was very intriguing too. However the world-building though tantalising wasn't enough for me. But that's my personal complaint. I always want more world-building, and Thea did create a fascinating reality where all sorts of paranormals living in the open.
Overall I wholly recommend this series (just skip book #2) and looking forward to Oracle's Moon which comes out in March next year.