Joomla:best on features, media capability, repurposing, templating, visuals, admin usability, ecommerce. The new core ACL system is not fully tested yet. SEO is very good, and in practice better than Drupal. Drupal: best ACL, high page numbers, stability. Not so good on templating, visuals, sysadmin usability. Solid code, gets more plaudits from other developers than Joomla's. SEO is good. CMS is better? Everyone please give your feedback.
Drupal is more stable platform than Joomla. Also, it is better in handling high page numbers due to its advanced management controls. Drupal and Joomla – both are good in handling high traffic. But Joomla is a simpler language to learn compared to Drupal. Both CMS have some positive points and some negative points. The final selection amongst these two totally depends on the requirements of the project.
Joomla is user friendly, easy to adapt and create templates for, anyone could build and customize a medium-big sites. For Drupal, you have to know what you`re doing, but can manage huge sites.