I very clearly remember not enjoying this when I was much younger, so finding that - to my slightly more grown-up self - it is, in fact, fantastic came as a little bit of a shock. I only re-read this because I had just read The Giver for the first time, and was desperate for some kind of answers in this sequel (there are no answers, really, but somehow this isn't disappointing). I suppose I was unaware how much my tastes really have changed since I was 13, especically as many of my favourites then are still favourites now (Inkheart, Harry Potter, Momo, Terry Pratchett etc).
Then again, I thought Twilight was the epitome of good writing at the time so I suppose things really have changed a lot.
Anyway, I digress. My point is, Gathering Blue is a fantastic book, especially if read (like The Giver) as a parable or fable. Simple but powerful story, and writing that doesn't get in the way of its purpose.