On CS: you are already using a compile step that dynamically changes code, how more complex can it get? I have thousands of lines of CS in production and it never caused any more problems than JS. If you think of CoffeeScript as a tool to write Javascript, not a separate language, things go much smoother (you want to debug the javascript output, not the cs source).
As I mentioned, I look forward to revisiting it when a standard toolset has matured.
If it actually does create more problems then it solves then a lot of people are just plain making a mistake by using it :) which I don't think is the case.
Plenty of programmers I know had a similar knee jerk reaction to the idea of CoffeeScript and have since decided it is a worth-while trade off.
You never know, you might be one of them!
I'll get into CoffeeScript when I feel that it solves more problems than it creates (it's very important for me to be able to debug raw source code in a language). My goal as a programmer is to reduce complexity, and I think it will take about 10 years for CoffeeScript to let me do that.
EDIT: Forget to mention, there's nothing in particular that caused me to write this. I just realized that, more and more, my style goes against what a lot of people do. I figured I'd document it for anyone interested in it. :)