Play vs Symfony

Play has quite a large community which provides numerous tutorials and videos related to developing with Play.
The Play official documentation covers many things, such as the framework itself but also specific stuff such as Akka, SBT and Netty.

There are also many big companies that base their main sites around Play, one of them is LinkedIn which provides third-party documentation on a regular basis.

Play framework's convention over configuration methodology makes most Play projects have a very similar structure. This means that the code written for the framework is very readable. This enables a developer to switch between applications without having to relearn the ecosystem for every project. The built-in templating system also helps with code and makes it possible to have a very low count of lines of code.

Play is very simple to get started. The documentation is very helpful for beginners and advanced users alike and the official website has a great "Getting Started" tutorial to begin developing with Play.

Play Framework is asynchronous from the bottom up: asynchronous is default in Play API.

Play uses Akka for concurrency, Scala for a templating engine, Netty as a client-server framework and SBT (Simple Build Tool) for building. And they all come out of the box.
Play also comes with the option to scaffold your applications. Play is an all-embracing ecosystem designed to increase developer productivity and shorten development times.

Symfony is open source and released under the MIT license.

Symfony comes with a built-in toolbar that helps developers debug their applications during the development phase.

The toolbar is also extendable and new components, called panels can be added if needed to help with the debugging process.

One of the greatest strengths of Symfony is it's amazing and large plugin ecosystem, which comes as a result of it's large and dedicated community. Having a large number of plugins means less development time and more productivity.

Symfony has one of the most active communities out of all the PHP frameworks. This is shown by the high number of commits made every day in the GitHub repo.

Symfony makes you be a better programmer. You have to deal with the latest object-oriented design patterns such as service-oriented architecture, dependency injection, interface abstraction, and so on.

Symfony makes use of XML, YAML or PHP annotations to create configurations in order to tell Doctrine on how properties of a certain class should be.

Symfony has a powerful built-in event system that allows you to add flexibility to applications and makes it easier to maintain the codebase down the road.

Uses Twig, which is a simple and easy to learn templating language that can also be used as a standalone engine, outside the framework.

Symfony makes use of the Doctrine ORM to add an abstraction layer over the database in order to maintain flexibility without having unnecessary code duplication.