Reading people's comments here make me laugh a little bit. ASP.NET MVC been around a few years now and does that and a lot more in a very easy way and in a great platform. I find it really funny how people get commodity software and dress up as the next big thing.
It's pretty much the same as when Microsoft announced nuget after ruby gems and apt-get existed for so long. Why don't they just cut the bull out and call it for what it is?
I've gone from Java frameworks to ASP.NET MVC and back to Java. I really miss ASP.NET. I love the convention-over-configuration in Microsoft's stack. Is your class a controller? Call it SomeClassController and put it in the Controllers folder. That's it. Setting custom routes and doing URL rewriting was a piece of cake too.
I feel that when I try to do anything in Java I always have to consult the documentation which slows me down. The good thing is that there's plenty of it on the Internet but it's still a productivity drag.
I work with ASP.Net MVC primarily (since v1), but I think Play framework have a lot to offer in the JVM web development space.
The biggest key selling point for me is the 'hot' reloading: make changes in your code, refresh your browser, and see the changes immediately. You don't need the whole project to be rebuilt. As far as I am aware, this is what makes Play unique. The 'hot' reloading is probably the reason why it's useful to show nicely formatted errors in the browser (during dev / debug mode), you can see immediately where you stuffed up soon after browser refresh. Errors are also pushed to the console.
However, I realise that ASP.Net MVC View templates can be updated during debugging session, I only wish to be able to do the same with the .Net classes without having to rebuild it.
Plus, being on the JVM you'll have plenty of PaaS deployment options for cloud hosting provider (e.g. Google App Engine, Heroku, OpenShift).
With ASP.NET if you are in a 32 bit machine (who still is?) you have edit and continue so you can do the same as in Play. AFAIK they are working to bring that to 64 bit machines too.
Don't understand me wrong. I see a lot of value in Play. My only beef is with the "this the awesomest thing you'll ever see" approach to selling it.
It's pretty much the same as when Microsoft announced nuget after ruby gems and apt-get existed for so long. Why don't they just cut the bull out and call it for what it is?