I come from a very strong java background. So my answer here could be a little biased.
Play finally brings to the java community what django has been for all these years in the python community, but just a way better.
Play is built on the jvm therefore inheritance all the goodies from a solid platform that has been proving over the years to be the most reliable and scalable one that allows to write and run applications at scale.
I want to say that I did try django. Its popularity among the web community made me curios and I wanted to give it a try.
Strangely I did not find it as easy to use as I had expected.
So many configurations. Too may libraries doing the same thing and often not play very well with each other. A way too much magic.
Furthermore, not having type safety makes very hard to manage and maintain
web application at big scale.
Don't get me wrong, I am pretty sure that people managed to do it, but in my experience I still find java/scala best suited for this, especially when you share the code base with a lot of other developers.
IDE support for Java it is unbeatable. If you implement TDD you will find yourself refactoring code and moving things around on the daily basis. And java IDEs give you all this power. With type safety and more.
My take away is that as long as you find yourself writing a simple CRUD application/prototype/toy without even thinking too much of advanced features and big scale then you can probably find some advantages on using python/django. Otherwise the whole java ecosystem wins hands down. And play is the cherry on top.