Do my users think the app is interesting or valuable?

  Yes. Because sometimes SMB like ebayer only need to create invoice but don't want fancy quickbook

Did my users use the app as I intended?

  Yes. They can navigate without instruction

Did my users encounter any bugs or broken features?

  Yes. Some css bugs.

Did my users understand how to use the app?

  Yes. The app itself is very easy to use.

Summary:

  User expect app to be mobile friendly and also want extra feature like shortcut to add customer instead of doing it on main page. Other than that, testing this app is smooth and fun