Overhyped and overrated, in my opinion.
Oh, I know this is the sort of story that some reviewers would love - there is plenty to analyse and write about, certainly, but there is not one story ever told that would please everybody who read it, and this story I did not like. But to be fair, I doubted I was going to like a story involving unicorns. I merely read it because I was curious and wanted to form my own opinion of the story.
So, it's about a girl called Barbara and her unicorn Sunny, and to fit in she has to sacrifice her Unicorn's horn and wings, turning Sunny into a Pony, because that's what happens to all the Unicorns when they go to The Party. They become Ponies. I have no objection to the storyline - it is just not one that interests me particularly, because I never was and still am not the girl who desired to fit in. When I was in school, I spent my lunch breaks in the library, surrounded by books, and if I had been Barbara, we would have stayed at home and read books together.
There is so much symbolism in this story - I'm sure that if you think about it, the horn, the wings and the voice each represent something. Wings, for example, could easily represent freedom, that you have to give up to be one of the crowd, because there are rules, then, that must be followed if you do not want to be an outcast. This story, despite its fantasy setting, with improbable mythical creatures, parallels much of real life - in particular the social interaction; the desire to fit in that applies to many people regardless of their age. And it is sometimes very sad, that when people succumb to peer pressure , they do things that they had no wish to do because they felt that they had no other choice.
This story spun its way to its tragic end - as shown by the cover, thus not a spoiler - Again, there is a parallel with real life, that people do not like it when others are different. You can draw comparisons between Barbara not being accepted because she was a Girl Who Does Not Have A Pony, with many other things - such as racism, classism, sexism, etc.
My verdict, in short, is that: As a story, this was well thought out and well-written, yes, very much so. But its entertainment value is virtually nil to me.