Yes, it requires some work because you have to follow certain guidelines when writing the reviews. Writing 150-300 word reviews can seem like torture when you're reading a book that you wouldn't personally choose even if you were snowed in for weeks with nothing else to do. You also have very little control over what genre or format (picture book, chapter book, etc.).
Here's a list of some of my favorites that I've had the pleasure to review:
Fourth Grade Fairy: Wishes for Beginners by Eileen Cook
Escape from Planet Yastol by Pamela F. Service
Flat Broke by Gary Paulsen
Escape From Zobadak by Brad Gallagher