CoffeeScript novice here. Can someone please tell me why/why not coffee script should be used rather than JS? Is it usable in serious prod level projects? Looks very clean.
It's definitely usable in serious production-level projects. I use it regularly and quite enjoy it. I don't have much time right now but to sum it up: it takes the (IMO hidden) expressiveness of Javascript and brings it into the light.
I feel like it gives me a 10x increase in productivity when coding JavaScript projects. I consider it irresponsible to not use it.
All of my projects have been in Coffeescript since 3 years ago (over 100k lines of code). Have had almost little to no problems. Like you, feel 10x more productive when I'm using it!
As fair as I know it's used by Palantir and Dropbox in prod (just to name the big ones).