Here are some of the projects that have used Symfony framework effectively
Founded in 2005, Symfony Framework is actively supported and evolved following current trends. Symfony code is created using the correct design patterns. Symfony uses ORM Doctrine, which allows you to work with a large number of databases (PDO, SQLite, PostgreSQL, MySQL), which hints at a wide range of Symfony uses.
Also ideal for "fast" medium or large projects, with frequent business process changes and long support times.