I spent 2010 learning a range of Content Management Systems (CMS) starting with Drupal, moving onto WordPress and finishing on Joomla.
In comparing Drupal to Joomla, Drupal does not compare. Joomla will allow you to develop a system rapidly and efficiently with a strict taxonomy. It is set up with a structure of categories, sections and articles, which loosely correlate to pages.
The user access is set up and ready to use with pre-set levels of authorisation and as long as you play by the rules, it allows you to create a secure environment for large scale sites.
The developer community are on hand to produce handy modules for you to exploit at your leisure although some may set you back a few bob.
Joomla have moved onto a fast release cycle for 2012 so it will be interesting to see how it develops in the future.