I have read 15 all together and abandoned one (sorry Natalie Babbitt!) but this one is currently vying to be my favorite.
Like lots of these books, the characters are a little too perfect, even in their imperfections. The kids are always a little too self-aware and make the courageous choices you hope your child will make. The adults a little too understanding or the coincidences in their lives are a little too far fetched.
That being said, and even with its heavy New York Yankee undercurrent (it's the late 60's so it's a Yankee team steeped in history and universally loved), this one is pretty good.