Some readers have found this novel's flaws to be off-putting enough to rate a lower score. I agree about a few of those flaws: the extraordinarily large number of references to other books was tiring at times; some story events unfolded in a way, or didn't, that seemed strange; and some things may have been given too much emphasis because they later seemed to have no importance.
But maybe it is okay if a story has some loose ends. What's the big deal? Especially if other things recommend it, such as its portrayal of magic and the way it incorporates fairies, creatures I've never found interesting, except I guess in Shakespeare, but that are well-portrayed here. The setting mixes magic into our world but is too sublime to be classified as urban fantasy, as far as I'm concerned. This is not a droll tale with wise-cracking succubi. I can't overemphasise how beautifully and seamlessly the magic infuses Mori Phelp's world, but ordinary things do too. She's fifteen, with a fifteen year old's concerns, some of which include ordinary things like friends and sex. Her voice is intimate, because we are reading her diary. A past event dominates a lot of the story. Mori survived a showdown with a witch who happens to be her mother, but we don't see that. We see the aftermath, when Mori is at a boarding school in England. There is some excitement, some enchantment, but a lot of it is ordinary, in a good way, often in a very good way. She begins to surround herself with a few good friends, none of them from her school, and there is a showdown that seems to puzzle quite a few readers and leave them unsatisfied. It puzzled me too, but it transformed Mori in a way that was convincing and left me with that feeling good endings produce.