I have just started to learn Python and Django after read a lot of questions about "Ruby/Rails vs Python/Django". I worked with Node.js since 2011 and with Play last year.
With Java. IMHO Play framework make more agile the web development with Java, I think that it's similar to Rails. I had some problems with its Ebean ORM and MySQL, also the scala templates have some limitations (e.g. I couldn't declare a variable). I chose Play because in my college all knows Java, and at that moment Play was the better framework for web development with Java. It's my project with Play Framework 2 : http://www.youtube.com/watch?v=i5Uf3N1rgWc and I'm going to still work with Play sometimes.