Thanks for this super plugin; as others have commented the caching / performance results can be significant.
Unfortunately, we've run into a problem when used with http://wordpress.org/extend/plugins/wp-pagenavi/, a plugin that adds advanced page navigation to a page.
When db-cache is active, the "count" of pages is off (i.e. it should show page 1 of 10, for example, but only shows page 1 of 5). If we clear the cache things appear to correct itself, but briefly. I discovered that even after de-activating db-cache, sometimes the only way to get the page numbering was to delete /wp-content/db.php.
Any thoughts as to what might be causing the conflict? I've tried lots of combinations of activating / deactivating the plugins in different order but still end up with the same results.