This is a new development branch of the add-on with almost everything rewritten to support XenForo 1.2, all existing features (group tagging, email alert, TinyMCE Quattro support) from the old version are updated to work in conjunction with built-in tagging. From this version onward, XenForo 1.1.* and below are not support anymore.
If you do not use any of the above features and has upgraded to 1.2, it's safe to uninstall the add-on now.
Regarding future development: next releases of XenForo may provide overlapping features with this add-on, until then this add-on will still be maintained and takes suggestion to improve itself.