Hands down, the book bag feature is the easiest. And it is possibly the easiest way for a patron to add multiple items from home, too.

For some users, it might seem a bit intimidating at first. However, it seems friendly enough to work your way though with a little encouragement.

In some ways it reminds me of learning to use self-check. You have to be willing to learn something new (it's that bell curve of early adopters, etc.). The reward is a certain amount of empowerment to be able to do things for yourself.