I was charmed by this book. From the very beginning, when we first meet Mor and Mor, there was a mystery - What's going on, exactly? What has gone on? How much of this is in the girls' heads?
Then off to boarding school, where we empathize with Mor's feelings of loss and isolation.
There several things that drew me to the book: an ability to identify with Mor's love of SF, and desire to talk to someone about it (and books in general), the fact that the story can be considered to be set during "what happened after", and the coming-of-age aspects, where Mor attempts to figure out who she is and who she wants to become.

I really liked the way that magic was handled (and not handled) in this book - much more satisfying than the wish-fulfillment in the Harry Potter book.
The language was nice - not particularly flat, but not as arresting as some. I found myself smiling over passages, but not so much for the beauty of the words, rather for how I identified with the quotes, e.g. "There are some awful things in the world, it's true, but there are also some great books."

I'd be inclined to recommend the book to teens as well as adults, but parents be warned - Mor's 15 and at an all-girl boarding school. There are discussions of such "disturbing" topics as sex, homosexuality, masturbation, spells, and fairies. Nothing prurient, but people Have Views...