• Joomla has got better Administrative control panel, while in Drupal there is nothing like adminstrative panel, when you login as an admin you will find more controls and more menus.
• The design part is better in Joomla. The sites built in Joomla will look better with lesser efforts. Many beautiful, attractive templates are available for Joomla.
• To build complex and scalable site I would prefer Drupal because it has got hundreds of readymade modules plus it's relatively easy to build complex functionalities in Drupal.
• A new beginner might find it easy to work with Joomla rather then Drupal but many of the developers/programmers lean to Drupal after they get enough familiarity with both.
• In Drupal, PHP code can be written on pages or any content you are creating. In joomla this facility isn't available. If you want to add code then you will have to edit the component files.
• Content categorization is lot better in Drupal then Joomla. I found only 2 level of content categorization in Joomla that is not at all sufficient for any content based site. May be additional component might offer categorization of content in Joomla but in Drupal it is very nicely managed by Taxonomy Module (available with Drupal core).
• Joomla has got in built WYSIWYG editor for content adding/editing while in Drupal you have to install WYSIWYG editor as a module.
• Regarding performance, I would say that it will depend a lot on how big your site is and in what manner have you configured your server and your CMS (Drupal/Joomla).
• Community is much more helpful in Drupal rather then Joomla. You will find help/support very faster in Drupal forums.

So here is what I think about Drupal and Joomla. Please let me know what are your opinions regarding both. Please add your views in comment.

Source: Difference between Drupal and Joomla | Mittal Patel's website