The difference is that CF is very close to javascript and makes it very easy to transition. But of course, if you prefer python, why not :)

Talking about future support, as CF is included in Rails 3.1, I guess that it should be guaranteed enough.

I looked in to it. While technically possible it looks like you'll have to include a script to implement the python-like objects. That's a bit more than I wanted, just to write javascript in python syntax... so I guess it's not very practical.