Dude! I finished it on friday and raced out to get second foundation.
The entire second half of the book I had a strong feeling that's who the mule was going to be, but he's just such a good character and the fact that the story doesn't end there is fascinating! I'm pouding through the third one now.
Also, I love the fact the Futurama stole the idea for the holophoner from this. I just imagined magnifico as fry.