The recommendation from Microsoft for Visual Studio 2010 is to setup all your tests to use test categories instead of test lists so you don't have to continue updating the .vsmdi file and for more flexibility in running them. However, when setting up a
"testing check-in policy", you HAVE to use test lists because it doesn't support categories. Seems to me, the "Testing Check-in Policy" that is included with the powertools should be changed to also allow selecting test categories.
"You can use test lists to run your build verification tests, but test categories are recommended for use over the test lists functionality from earlier versions of Microsoft Visual Studio 2010..., unless you have to create a check-in policy which requires
a test list."