I find it very difficult to review books in series before I've read the whole series. I don't know why this is. Nonetheless, I usually wait until I have completed the series before I write the review. If I DNF the series because I lose interest, there's a good chance I'll never post a review.
So, because I'll be talking about the series as a whole, There May Be Spoilers.
Proceed at your own risk.
I really, really enjoyed this series. It is a combination of speculative fiction and historical fiction - an AU version of New England, where witches are real, and the Puritans have installed a theocracy of extremely religious men who oppress women.
There were a lot of things to like in the series. The detail in the world building was convincing, and occasionally wry - for example, Ms. Spotswood created a world in which Dubai and the Middle East was a model of progressivism and women's rights for the world. The meshing of history and speculative elements was really quite good.
The other thing about the series that I really enjoyed were the sibling relationships between Cate, the eldest, Maura, the middle, and Tess, the youngest. I don't have a sister, but there was nothing treacle sweet about the relationships between these three girls. They were real, occasionally angry and, yes, there was convincing jealousy between the sisters. Cate was a bit controlling, and all too maternal. Maura was continually fighting for a place of visibility, stuck as she was between two sisters who both outshone her at various times. And Tess, the youngest sibling was fighting to be taken seriously. I know from reading Ms. Spotswood's blog that she has sisters, and I like the fact that she didn't just show us the sweet side of sisterhood - she showed us the rivalry, the family dynamic that isn't always warm and fuzzy.
In terms of strength of narrative, I liked all three books. Book 2 ended on a cliffhanger that really, really pissed me off. Maura did something that was so mean, so incredibly callous, that I, as a reader, was left angry and astonished. Book 3 dealt with that event in a way that I found convincing and that provided hope of a resolution, but without an easy restoration.
Which brings me to the romance between Cate and Finn. I really liked the way that the author developed their relationship. It was a functional romance between two individuals who were equals. There was no creepy behavior masquerading as seduction, and Finn admired Cate's committment to freedom for women as well as her pretty face. I was pretty irritated at the end of book 2 because I felt like the plot twist was gratuitous. As it turned out, though, it wasn't. Book 3 convinced me that it was necessary for Maura to do what she did. I still don't like it, but I get it.
The end of the series reminded me a bit of the end of Mockingjay. There was no neat resolution, no "fixing" of the societal problems in a pat and easy wrap up. We were left with a New England that we can hope changed for the better, that was less oppressive of women as a class, witches in particular, and the disempowered masses in general. But there was a lot of work to be done to build a better community. And the romantic arc between Finn and Cate was wrapped up, too, in a way that made sense.
I love books about witches. This series was satisfying and I really enjoyed it. I'd recommend to people who enjoy YA, who enjoy witches, and who enjoy alternative history/speculative fiction. It's a solid 3 star, not quite 4 star series.