I have little to add, but I'd make a similar case for Scala. If you're tied to the JVM or existing code, or don't want to make the leap to laziness/purity/immutability for everything from day 1, Scala can be a smoother way to learn these new concepts (which will ultimately make you more productive whichever language you use).

(And if you're going to use Play, Scala is very much the best way to do so)