The beta’s working well. It’s still throwing an error because of the isset() on lines 476 of mediatags_settings.php. switching to !empty() would get rid of the error.
Might be worth adding to the FAQ that if you have SSL enabled only for admin pages or per-content (when using a plugin like Better WordPress Security, for instance) the “Media-tags” in the Media Library’s “Bulk actions” pull-down may not have any obvious effect. This can be fixed by configuring the browser to allow “mixed content” – loading scripts via http even though the rest of the session is https (google “mixed content” and your browser version to get appropriate instructions).
Thanks very much for the plugin, and for letting us try out the beta !