I am exploring play for my next project, and all i can say is i am thoroughly impressed. With typesafe providing resources, i am hoping this seriously dents J2EE stacks.
A few "renegades" are using JBoss for some small one-offs, but nothing in their main processing stacks. With open source, there's no one to sue, no one to hold to the fire, and "only hippies write systems with it"(a paraphrase, obviously).
It crushes my soul. (But pays my mortgage.) I'm really conflicted as to my future, honestly.
Again, this is a very narrow view of a very limited scope, so I'd be anxious to hear other people's experience.