Symfony2 is recognized in the PHP ecosystem as a very well-written and well-maintained framework. Design patterns that are recommended and forced within the framework allow work to be more efficient in the group, this allows better tests and the creation of reusable code.
Symfony's knowledge can also be verified through a certificate system, and this allows its developers to be easily found and be more recognized on the market. Last but not least, the Symfony2 components are used as parts of other projects, for example, look at the following:
Drupal
phpBB
Laravel
eZ Publish and more
Over time, there is a good chance that you will find the parts of the Symfony2 components within other open source solutions.
Bundles and extendable architecture are also some of the key Symfony2 features.
They not only allow you to make your work easier through the easy development of reusable code, but also allows you to find smaller or larger pieces of code that you can embed and use within your project to speed up and make your work faster.
The standards of Symfony2 also make it easier to catch errors and to write high-quality code; its community is growing every year.