Understanding that this is the story of a villain, not a hero, is what made this book for me.
And I think that's why some are disappointed in it. Because they expected Adelina to be a hero. She's not. She's a darkly beautiful villain, and I love it. The story makes a point of showing her conflicted thoughts and views, and the darkness within her that slowly takes over. It's nothing I've ever seen before. I love it. I love how we get to see how little things people do (such as the Daggers not fully trusting her, thus confirming everything her father said) effect Adelina and bring the darkness and the anger forward. We see the beginnings of a rather scary villain. And I love it.
Also, I love the world! The island country of Kenettra is so rich and beautiful. I love the glimpses of culture we see alongside the rest of the plot. Some of the best world-building I've seen in a while.
Everything about this is beautiful, and I'd totally recommend it!