I like that it is very customizable, especially when you use modules which are available in their marketplace or can be created yourself using composer (which has an amazing community of developers) - just make sure to pay attention what's being used by other people as well for your project! Also there have been some security issues with symphony recently so they need more time until everything will work fine again but nothing really bad happened yet since my last update was nearly 2 years ago :) It makes sense if all those who plan web applications should know how databases store data because this module allows me do exactly such thing without having much experience about database design before building any application at least from scratch ;) The only downside i see currently could maybe relate directly also back then to Symfony2 itself not fully developed enough/stable etc., however now things got better though still far away form perfect state :).