Lois Lowry was another author that I adored as a child with her series about Anastasia Krupnik. I hadn't realised that she was also a winner of the Newbury Medal (the American equivalent of the Carnegie Medal - judged by Librarians) in 1994 for this book, The Giver. It's completely different to her other books, and I honestly couldn't tell you if I'd read it when I was still at school.
This is science fiction for younger readers, so some of the themes aren't as developed as they might be in a full blown adult sci-fi. This may be a deal breaker for some adult readers, but it really shouldn't affect it's intended audience (compare to Stephenie Meyer or J K Rowling!) or those willing to suspend a bit of belief.
I can see why it earned it's Newbury medal - it's well written but easy to read, it's certainly delivers on developing the reader and giving a lasting experience from the book.
It's also been done many times since in YA fiction - clearly the greatest form of flattery!