If you're interested in testing the UX of an individual ad tag, you can find this data by clicking 'View' for a given ad:

Currently we gather performance metrics for the ad load, broken down by domain and by content type (HTML, Javascript, etc.).

You can also preview the ad in your browser (for QA/troubleshooting) and view an interactive network timeline to quickly spot issues:

We have much more planned here, but let us know if you have any questions or ideas!