f0dder, can you conmpare RoR and ASP.net?
Just on the size of community alone, ruby has a big advantage. But I've never looked at any ASP.net code, and the only 'serious' site I know built with it is SO.

I have some experience with Django. There, we can talk :)

You can try it here: http://meta.discourse.org/popular/more

What I like:
- Tech stack is better; Rails + ember.js
- The team really understands communication, having made a big product in the area

Mouser, would you be brave enough to move DC to discourse? :)

Javascript has changed a lot in the last 5 years.
the most transformative things are happening. One can sorta write large apps on it now.
Testing is ... ok.
CoffeeScript gives you classical inheritance.
Node is much faster than any other thing you may use on the server side for a web app (php, python, ruby).

And... it's on phones. The way things are, you need to think how your app may be used on a tablet or phone. :)