Here at Springtimesoft we love Raygun and use it for all our error tracking. In cooperation with Mindscape, the company behind Raygun, we have developed the official Magento provider for the Raygun error reporting and tracking service that you can find at Raygun on Magento Connect.
As it is open source you can contribute yourself if you’re keen: https://github.com/springtimesoft/springtimesoft_raygun
Screenshots
Settings page.
Advanced settings.