Ok, so, thoughts.
This book has a lot of flaws.
The proportions for this book are way off. The introduction of the quest is very short and we don't get much of an explanation. This will be more or less fixed later in the story (or the author tries, at least), but nevertheless... Then, most of the book tells of the journey the characters take to the fairy city Taninli. This easily takes up two-thirds or more of the book. By the time they reach the city, there is not much space left to tell the rest of the story and it all feels quite hurried. Especially the final event, where Kaede has to hurry to meet the unicorn in order to safe the fairy queen is ridiculously short and hurried. I wish the author had left some of the journey out and would give more details in those last parts instead.
Another big flaw is the portrayal of good and evil. The 'bad person' in this book (Elowen) is extremely two-dimensional. 'Evil' is portrayed black-and-white and the author attempts to explain Elowen's actions to make it more grey but fails. I also felt no emotion whatsoever for the fairy queen later on, although I think the author tried.
That said, I must also be fair and say: the book was never boring. The writing style was also quite pleasant. Although the amount of adjectives put me off at the beginning of the book (probably because I of the book I read before this, which was a masterpiece in my opinion), I began to like the style later on and the book was a quick read. It wasn't a terrible book, but I was expecting more. I've read plenty of young adult books with far more depth.
Another plus for the book: the world is interesting enough, although I wish we got to hear more about it (but perhaps that happened in Ash, which is apparently the same world?). I liked that sexuality was almost a non-issue in this world. Kudos.
I'm giving this book 2.5 stars, leaning more towards 3.