Drupal and Joomla are both open source CMS, so which is better?
What is it?
Drupal - Developers choice, if you are the type of individual who thrives on hand-coded content and scripts. In comparison to other Content Management Systems (CMS), Drupal, relates more to the developer as its structure is more script based. This platform may not be strictly for designers unless they are willing to commit to the development side of web design and web functionality.
As being a CMS the functionality is quite similar to other popular choice, and for the sake of comparison: Joomla. When we talk about a functionality we think of the necessary features, blogs, comment section, author's name, etc. Drupal, in its essentials, can function similar to any standard blog you see on the web today. However, the capabilities expand farther beyond the releam of blogging, and thrives, when building large dynamic sites.
Joomla - The name Joomla literally means "all together", with that in mind comes the theory that the CMS would live up to its name. In comparison to Drupal, code-wise, Joomla falls short, for designers and artist a like, Joomla is more favoured as the support for themes is much larger based than Drupal. If you looking for a well designed theme with the basic functionalities of the standard "web 2.0" blog, Joomla is a more favourable option.
In comparison to the two CMSs there is no better option but rather a personal preference or skill set. If you are more developer oriented, and do not mind the learning curve of Drupal, then Drupal would be the favourite of the two, if you are more on the art or design side, then Joomla would be the better choice, its not to say that a designer can not choose Drupal or a developer should not use Joomla once again it comes down to a matter of preference. Install both on a test server and see which one suites your needs accurately.