The binders they're distributed in use flexible plastic sleeves to store the disks. They fit the sleeves tightly, and they tend to grab the sticky sleeve surfaces. It's simply not possible to remove a disk without fingerprinting its sensitive surface, whether driving or not. Dirty disks skip in a particularly annoying way. The librarians say that they have to periodically clean the disks to keep performance acceptable.
CDs are about an hour long each, which is good.
When I turn the player off I always forget. I don't believe that's a problem with a built-in CD player. In short, I love the idea of books on CD, but I don't believe they're ready for easy travel use yet. If you're thinking about getting a portable CD player, you'll find a lot of them out there. Yesterday, one day past its warranty period, the disk section of my player went south.