Symfony is an open PHP framework. It presents an architectural pattern "model-view-controller" (used in the flexible software design).
Symfony also automates the most common Web tasks. This helps to create and maintain Web applications more quickly and save time on solving trivial problems.
Another advantage is that it allows developers to customize almost any configuration items (from pages directory to structure libraries).
Symfony is sufficiently flexible technology, so you can create projects of various types. For example, painlessly expand sites. This framework can be adapted to your needs, using the necessary components. This makes it extremely useful during creating a site based on Drupal.