I just realized that the entire time I've had XCache installed, I never actually configured it in the php.ini to run.
Today, I changed the default xcache.size variable from 0M to 32M and now xcache admin shows stats.
However, when looking at xcache admin, it only shows php cached files from the admin interface, not the rest of the site.
This sounds like the above post. I've searched the forums and cannot find a solution. SuExec is disabled.