I am having the same problem as huckmag.
Generally, both the WP-Cache and WP-Super Cache work very well - the caching and everything else works and is fabulous.
However, when I edit a post as an administrator or have anyone write a comment for a post, the supercache for that post does not get expired and refreshed. So users who are not logged in or never left a comment will still get the old supercached copy of the post.
I have physically verified the files in /wp-content/cache/supercache directories and confirmed that the index.html files for each post do not get updated even after an edit or new comment.
I have ruled out plugins, because I disabled all plugins except for Akismet and WP-Super Cache and the problem still persists.
I have ruled out themes, because I switched to one of the two plain vanilla wordpress default themes, and the problem still persists. (I'm using K2 normally, BTW)
Everytime I do the test I always clear my cache and verify in /wp-content/cache/ that the files are indeed deleted.
I'm running WordPress 2.6.2 on Host Gator and my PHP info is here:
For the time being, I'm switching to HALF-ON mode, but is there something else that I can try to help and troubleshoot this?
Would really like to get this otherwise awesome plugin to work fully.