Joomla vs Drupal
- Drupal allows you to assign content to several Sections/Categories, while Joomla only supports one Section and one Category for each Article.
- Drupal supports multi-site setups, so a migration from " multi-site with Drupal" to Joomla must be put into a certain site.
- Drupal has built-in forum discussion and you don't need to install any additional modules.
- "Blog" term in Joomla is actually a teaser of contents : Title, Introduction and a Read More link. It's not the same as blog in Internet dictionary.So, Joomla supports a 'Blog' by default, but with a different meaning.
- Comments on contents are not available in Joomla by default, but Drupal supports comments for all content-types by default.
Find more in drupal.org