I finished "Son of a Witch" this weekend. Soo good. "Wicked" was better, but I think that's because he had more background to draw from with the original Oz story. I also think Maguire set himself up for a third novel! Yippee!
The next book I have to read from him is "Lost." This one is based on Scrooge. Should be very interesting.
I highly recommend anything this guy has written. It's not always very family-friendly, but it's definitely excellent reading and, might I even say, literary genius.