Choosing the best framework for rapid development has been a topic that has been debated to death. Today, there is no longer “the best framework” because all modern day framework is scalable and robust, they learn from each other. They are all adapting very fast to new techniques of doing things.
At the time of writing, nodejs and rails continue to innovate with php chasing fast behind. They have all very similar development methodology, so knowing one framework well means you can jump between other modern day frameworks easily.
For php, its Laravel and Symfony. if you want to invest your time, I recommend symfony because it is more stable when compared to the rest. Symfony components have been used by many projects including Drupal and Laravel.
as for Django and Rails, I am leaning more towards rails.
Symfony 2 is a mature framework. A mature framework means information and libraries don’t get outdated quickly. Some framework moves so fast that the 3rd party libraries couldn’t catch up. Rails early days suffered from this. Nothing worked out of the box because googled information was often outdated. Choose a stable framework so that you don’t spend lots of time setting up the right environment and troubleshooting the libraries for example. You should be spending more productive time learning the software.