Originally Posted by RTW1

It rather depends on what "advanced" passbook features they have implemented.

The most basic implementation gives you an overview of all your reservations/tickets in one application, something that can be a little more organized than your mailbox.

When using the more advance features your reservation will pop-up based on time and/or location. And even better, some will refresh the information so you can get a message giving you the gate or the actual departure time.

It's not a bad application at the moment, but it still needs some work. And more participants will also help.