The backend features of Mambo are very extensive, have you checked out the demos? Frontend Demo , Backend Demo , login using, Username : admin Password : admin. Depending on the content of your website, it could work for you. If you need features like article ratings, user comments, it has it, some features require modules to be installed to function, and they can be downloaded at various Mambo resource sites. It is fairly easy to use, it might take some time getting used to it, how to add/delete/edit and move content pages. I've switched back and forth a couple of times between XOOPS and Mambo, and some others. I'm using it right now on some sites with various articles. The current version is 4.5.2 and can be downloaded from here . Template demos are here .
The following sites let your test out other CMS out there besides Mambo.
http://www.opensourcecms.com/ (running Mambo)
Compare different CMS
http://www.cmsmatrix.org/
http://www.cmsreview.com/