Ranked in these QuestionsQuestion Ranking
Pro Active community
Drupal have one of biggest and more active communities across FOSS, maintaining a large and vibrant ecosystem of extensions and installation profiles.
Pro Free and open source
Drupal is free to use and open source.
Pro Excellent SEO
Drupal was designed from the beginning to follow best practices in regards to SEO.
Pro Highly customizable
Drupal can be customized to do almost anything. It was built ground up with the intent of using a wide variety of small modules to get the exact result wanted instead of just the most common solutions.
Pro Great for enterprise use
Drupal is stable, with powerful version control and access control methods and can handle large amounts of traffic.
Drupal 8 has REST services built in.
Pro Multi-lingual support
Starting with Drupal 8, there's built-in multi-lingual support.
Pro Drupal has full SEO capabilities
(vs Joomla, which lacks SEO capabilities), there is an essential issue for promotion.
Pro Good accessibility
Pro Semantic HTML5
Pro Great templating engine
Pro It's easy to transfer config changes from dev to production
Pro Responsive front-end and back-end
Drupal 8 follows responsive design philosophy out of the box, both front-end and back-end.
Con High resource consumption
A more complex Dupal installation can easily exhaust 256 MB of RAM with only one or two visitors.
Con Steep learning curve
Drupal is not easy to get into and out of the box doesn't offer much. To get Drupal doing what you want it to, modules are required. To get modules, an understanding of how Drupal works is required. And that takes time.
Con Lacks good free modules and themes
Most good third-party modules and themes are costly.