So far I’m still getting to know the application but it seems quite good and in a corporate environment like the one I work at the mail integration and access control features are essential. I’m tempted to try a full trial license during August, with the JIRA integration also.
Will see how my personal evaluation goes. In the meantime, check the notes that Rui took with his installation. One thing though: it’s not closed source. You get full source code with the commercial versions of Confluence.