If you compare these two CMS and try to evaluate then you will always come to a conclusion that users using Joomla loves Joomla and Drupal users loves Drupal.
Drupal has superior architecture and it also has very SEO friendly platform. Drupal is always known for its sound and sturdy build. Drupal is used by large organization as it is a content management system for big projects as it has rock solid and high quality platform. Joomla is comparatively easy to install and setup but only one site can be developed per installation.
Compared to Joomla, Drupal is better when it comes to ability for non-technical people to learn the CMS interface, maintenance and upgrading, ability to create a new and functioning website quickly, and ability to teach clients to use their CMS more effectively. Joomla is used more by beginners comparatively as it has easy to use interface, gets install easily and in less amount of time.
Joomla is not as sophisticated as Drupal and it cannot perform as well as Drupal. Moreover, Joomla is not SEO friendly and it is used more by those who wants to create their personal websites or by those who just started working with web design. Joomla is basically not advisable for creating high-end websites. While Drupal is being used by many high profile sites like MTV UK, BBC, NASA, etc.
Drupal is rated higher than Joomla because of its support with multimedia, social networking, SSL, forums, event calendar, Blogging, document management, internationalization, user management and permission features, ease of external integration and developing large complex websites and quality of add-on for enhancing functionality.
Drupal can work with Apache and IIS while Joomla supports only Apache. Joomla supports SSL log-ins and SSL pages while Drupal doesn’t support them. Drupal has inbuilt Translation manager while Joomla has a free add-on for the same purpose.
So basically both of these content management systems are great tools it just depends on the nature of the project and functionalities of the project for which you require them.