I loved how much I was able to learn about the publishing industry as a whole and all of the knowledgeable people I got to talk to.
What I wish was different
I wish I'd had more individual projects to work on, but it was wonderful to be a part of the book publishing and marketing process.
One piece of advice I would share about this experience would be to talk to as many people in as many different departments as you can while you are there. You never know what might pique your interest.