Data Export IO: Reports

This app does just what we need. We find it very flexible and easy to use. I should also mention that we had to contact the developer with an issue, and they responded very quickly and fixed the problem for us.
Update: a year and a half later, we're still using the app. It's a crucial part of our business, never fails us and the support is outstanding.
Update: we really appreciate the support - another custom report provided really quickly. An app you can really rely on.