First off, go to passsource.com to plug in some custom cards of your own.
The problem with Passbook seems to be that the concept most of us are thinking is NOT actually what the Passbook is. And thats not the fault of the user necessarily, but how the app was presented. After jumping through all the numerous hoops to get Walgreens/Target into my passbook then I realized that my mother would never figure this out so I gave up and decided that for a "convenience" app then this was pretty complicated.
Another issue I ran into was that I would like to use this app to hold discount codes (alphanumeric, not barcode). For example, I just got a redbox text today for a free movie so it seems like it would be perfect to just open passbook, read the code and then shred the paper. But that just isnt possible because of how difficult it is to get custom items into the Passbook.
Im not slamming it because its a new product. But I do feel that its a very poorly planned product so far and it needs to get better in a hurry or else it will be dismissed as a failure and get ignored.