I installed on Joomla 1.5 site and it's working great. Now I have installed on Joomla 2.5.8 and am really impressed. We'd spent hours loading up into another popular extension but found it inflexible and useless for a complex tree of documents. Fortunately we were able to point the documents folder to the one we'd already set up and off we went. A little bit of SQL and we carried over the categories and document entries.
We haven't gone live yet - but already I feel confident this is a great choice. The flexible layout configuration beats any of the other similar extensions hands down - simply brilliant!
Well done to the developer - awesome work. If you're looking for a download/document manager - this is the one!