It depends on your requirement.
Joomla CMS being a universal and open source management system can be adapted and used for almost any person that a person wants to.
Drupal CMS is an open source and free CMS, mostly used in larger enterprises. Written in PHP, Drupal CMS gives users the leeway to manage, publish, and update unlimited number of content on their websites.
It totaly depends on what functionality you want to have. If you are interested in multimedia or more complex functionality then Joomla is a better option. Thus when it comes to build up a complex and robust website full of features and functionality, you should go with Drupal.