I never gone too much deep over the symfony. However, I experienced it for one of my project. Adhering to an MVC pattern and strict object oriented language Symfony framework allows creating more testable code which can be reused in future and accordingly saves the time.
Choosing Symfony means having a long-term vision of application assets. It also means knowing how to make the day-to-day life of developers much easier.
The advantages of using symfony framework and the answers for the question why to choose symfony are:
1. Empowers Developers :
By taking features that would have previously have taken 100’s of lines of code and compressing them into one simple function call empowers developers to integrate more complex features into their Web Sites.
2. Allow for Quicker development of applications :
This is very relevant for people that need websites created in a very small window .
3. Lower Costs :
Allows programmers to pass cost savings onto the customer, a whole new range of customers generated that wanted a website but previously could not afford the higher development costs.
4. Symfony tries to bring innovation to PHP:
It was one of the first major frameworks to embrace PHP 5.3, to introduce the usage of a Dependency Injection container, and to use a templating engine for its templates by default, Twig, which is now also adopted by major CMSes like Drupal and eZpublish. Symfony also has some unique features like its gorgeous debug toolbar and its great built-in profiler.