Very easy to use and really the only extension available that was suitable for mass tagging over 5000 articles by topic. It has really improved the browsability and searchability of our site. It allowed us not only to create tags, but also tag groups - so that we can allow article browsing by location, subject, period covered etc. I can imagine so many ways it could be useful to Joomla content managers. It has a simple interface so that even people with minimal technical knowledge were able to assist in the tagging. Works great, have never had a problem with any of the features back or front end, and we've been using it for years.