There's only so many types of reviews you can write for children's books, before you start repeating yourself.
Anne Fine is an extremely talented writer. She was a part of my child-hood as I grew up and I also have enjoyed books she has written for older readers (I say books... I can only remember one...)
Basically, You've got to be a good author when you write little books for children with humour and a plot-line, and also you manage to get shortlisted for the Carnegie Medal. That takes skill.