I have now read all 3 books in the series and the first one is easily the weakest in my opinion.

The first half of the book is introduction to the world and our 2 main characters - Nahri, Ali - and through Nahri's eyes, Dara. Nahri and Dara are traveling to Daevabad and Dara spends that time reluctantly explaining things to Nahri, although never being fully forthcoming with that information. Also, cringey sexual tension is built up during this time. Really could have done without that.

One of my favorite parts of this book (and trilogy) is that not one character was purely good or bad, there's no obvious evil lurking in the darkness. There are separate tribes and factions within the world of the djinn and though many claim to be victims or saviors, none are innocent. Violence and duplicitousness and bigotry exist on every side. Too often in stories, it's obvious who the good guys are, it's easy to pick a side because one side is committing atrocities and the other is fighting to stop them. Here, the lines aren't always so clear. 
There's also the issues that are examined (to a greater extent in books 2 and 3). Power--what will you do, what principles or morals will you bend or abandon, to gain or maintain power? What kind of person will you become in pursuit of power and vengeance? Hate and bigotry and intolerance based on religion and blood purity pervade every part of this society, even with characters you like. 

The worldbuilding was very interesting to me and a lot of that is that I'm so unfamiliar with it. I assume that the inspiration for the magical creatures and beings is rooted in Middle Eastern folklore and mythology, and as such was completely new to me. This left me with no expectations for how creatures would behave or what they were capable of. I think the author did a beautiful job of weaving this folklore into a backdrop for an exciting story.

Now for the not-quite love triangle of Nahri, Dara, and Ali. It was handled in an interesting way. Who should Nahri trust? Ali, whom she's formed a friendship with based on shared passions but whose motives and loyalties aren't entirely clear, or Dara, who's super hot and protective and all broody, but hasn't been honest about his past and the things he's done? So glad the author avoided the typical love triangle trope that I hate with the fire of a thousand suns but at the same time, the Dara and Nahri relationship is fraught with serious issues, not least of which is that he's literally thousands of years old and she's about 20. I was happy when the problems with Dara and the way he forcefully took away Nahri's decisions was addressed in later books. 

While this book is far from perfect, it was largely enjoyable and it's a good set up for the 2 sequels.