I think CoffeeScript looks quite cool, but I'm afraid introducing a compilation layer will complicate my life and lead to weird issues which will cancel out any productivity gains. And while Javascript may not be perfect, it's good enough to get the job done.
What's the problem with the extra compilation step?
You can simple use coffeescript by adding "script type=text/coffeescript" tags to your code while developing, and when you are done, just compile and deploy. Or you can simply authomate the task (google for instructions).