It's good to hear you've found some of these metrics useful.

We recently incorporated all the metrics available as simple Maven2 plugins into our continuous integration system although we haven't spent time analysing the results yet.

I'll be doing this over the next couple of weeks so I'll get back to you on our experiences.

Currently we're migrating an external component into our codebase.

We're using coverage tools and metrics and have found them very useful indeed. We use Emma integrated into the IDE for real-time TDD coverage, Cobertura for CI unit testing coverage, and a combination of Selenium with Emma for integration test coverage.

The coverage tools keep us very focused, stop the team writing unecessary tests, and give me a quick overview of the current test effort.