I know coffeescript, and i use it for my main project, in parallel with Django. The project is particularly heavy on the client side.
I like having most of the conveniences of python, like list comprehensions, and it has a better syntax than javascript (i hate javascript syntax).
Also, coffeescript has some things that python hasn't, like a sane syntax for functions and lambdas, and some more (string interpolation is really neat when you're dealing with mostly text)
It does make things harder for debugging though, but i consider it a fair tradeoff.
I like coffeescript, but it is definitely a very young language. When I installed it, I had to modify the emacs editing mode because the language syntax had changed recently.
I still use it, though, because it's just so much nicer than JavaScript in every other way.
I like having most of the conveniences of python, like list comprehensions, and it has a better syntax than javascript (i hate javascript syntax).
Also, coffeescript has some things that python hasn't, like a sane syntax for functions and lambdas, and some more (string interpolation is really neat when you're dealing with mostly text)
It does make things harder for debugging though, but i consider it a fair tradeoff.