There are several Content Management Systems on the internet. The most popular ones are WordPress and Joomla.
Both installers are fast and easy to use. It can take up to a maximum of five minutes. The site is ready to operate after the installation, the system requirements are PHP and MySQL.
Themes can be purchased or downloaded from several sites. CSS and HTML knowledge gives a good opportunity to create custom designs. Responsive designs are available for both CMS.
WordPress is easier to use than Joomla, though both of them can be learnt in 30 minutes. Content creation in the two systems requires different approach and thinking
Joomla is very good for websites but it lacks several features that WordPress has and which make it much better for blogging. Professional bloggers recommend WordPress because it has the biggest potential to serve the blogging needs. It has built-in comment system and additional comment platforms (Facebook, Google+) can be utilized as well for free, while Joomla has a big disadvantage: it does not have comment system by default.
Joomla is better for a regular website than a blog, and for building complex sites. The speed of a Joomla site seems to be a little bit slower than WordPress ones. There is a popular e-commerce solution for Joomla: Virtuemart.
Both systems have hundreds or thousands of plugins. Joomla plugins mainly provide ideas for websites while WordPress plugins provide solutions for blogging problems.
Both systems are open source. This can lead to security issues as anybody can check the source code, though good plugins can solve this. MySQL database is the weakest part of the system, while third party plugins can cause security problems as well.
Daily backup must be performed as both systems are open source and can be hacked. There are some hosting providers who offer automatic daily backups. It can be done manually if there is no automatic solution.
Content Delivery Network
Both systems can be used with CDN, though some additional configuration is needed.
Fundamentally there is no difference between WordPress or Joomla. The default themes have good Page Speed results but custom themes can be less optimized.
It is hard to say which one is better than the other. WordPress is one of the bests open source platforms for blogging and Joomla is great for complex websites.