I loved everything about it, even if I know that for some this might seem slow. It is true that at the beginning it feels a little slow paced, but that is because it is important to the book to relate the long history of the O'Malleys (plus, the world building is very interesting to me in all fantasy books, so it really didn't bother me at all).
This book had magic, monsters, dark fairy tales, folklore, gothic elements on every single page and a strong, independent and feminist protagonist whom I admired a lot. I loved how the story made a point of focusing entirely on her ambitions and objectives, and while there were (romantic) interests they were not the focus, and they didn't matter at all and did not change the protagonist in any way. And yes, I love myself some romance in fantasy books, but it was so refreshing to see a woman who didn't let herself change for a man. I really loved that aspect.
Plus the story is very twisted, there are many subplots and mythology in there and secrets are revealed constantly. It hooked me up so much, I finished it in the blink of an eye.
So I definitely recommend this book to anyone who likes dark stories, fairy tales that have gone wrong, the Grimm brothers, witches, strong women and overall a good reading experience.