What is Symfony2 Framework?
A set of bundles containing configuration and bridge classes
These glue the components together, giving the developer a consistent experience
Symfony 2 is a PHP Framework for web development
Symfony 2 is MVC
Symfony 2 is OOP
Symfony 2 is not Symfony 1 (>=PHP 5.3)
Symfony 2 is HTTP-centric
Symfony 2 is like bits of Rails and like bits of Java
Why Symfony2?
Based on project needs Symfony can be used as:
Full framework
Micro framework (single file apps)
Symfony Components (stand alone)
Symfony comes with tight integration with many open source projects like Monolog, Assetic, Doctrine, Propel.
Powerful and easy routing.
Very advanced and useful template engine TWIG