In my opinion Drupal has virtues that make it be above its competitors, and although it has some cons, the balance is always in its favor.
First of all I have to say something that I repeat a lot, that Drupal is a great option, but it does not make it the only option for everything. It is important to evaluate the requirements of our project and see if Drupal fits in them, or opt for some other tool, being this another CMS or a framework. Knowing this, today we will focus on why choose Drupal and not another. For this I will try to give a review of the main features of this powerful CMS.
Tested a lot...
What I said before, the community!
The Drupal community is exceptional both in terms of size and level of participation. There are many users working to improve the core and modules and will not hesitate to help you with your doubts.
Thanks to the number of years in production and users using it, any security problem comes to light and is solved quickly. We also have a large number of modules to customize the security of our site.
Add new features in drupal is often as easy as a couple of clicks. In addition, if what you need does not exist, any developer will be able to create that feature by extending Drupal, with documented and own Drupal methods.
The Drupal administrative interface is extremely comfortable and easy to use. Maybe we can lose a little among many options, but once we learn more or less where each thing is, use it is very agile and intuitive.