This is a very strong beginning to the series. The world-building is especially good, with an intriguing mix of races and cultures, and tons of political conflicts between them. I especially admired the movement between city, rural village and the gypsy like encampment. Scarlet and Liall are terrific as the leads. The series of encounters with Scarlet trying to evade Liall's toll was one of the more original and satisfying meet-cutes I've found in a fantasy series. The author creates a great tension between the chaste (read uptight) Hilurin and the far more open Kasiri. The depiction Scarlet's relationship with his family is probably the best aspect of this book for me: I found it unusually sensitive and insightful, revealing Scarlet's character in a crucial way, and also Liall's though the implications will only really become clear in the third book.
Spoiler: My main problem has to do with Scarlet's chastity--There's no sex in this book; I missed it, and not just because I have a taste for smut. Scarlet's reluctance moved over into missishness for me; the author gives a bunch of good reasons for this, but none of them felt like quite enough--especially for a series where you know they will get together eventually. I'll pick up this thread in the review of the second book, where it was a much bigger problem. Luckily the story is adventurous and complex enough that you don't really mind.
All in all, I highly recommend the whole series.