I haven't used coffee script myself, but I think you'd be hard pressed to find someone that wrote something in CoffeeScript and regretted it. The biggest arguments against using CoffeeScript (or any language that compiles to JavaScript) that I seem to keep hearing are:
1. JavaScript isn't a very readable language. (I think this is untrue. I've seen some incredibly well written / structured JS)
2. Not everyone knows CoffeeScript, so when you put a project up on GitHub and it's written in CoffeeScript, it's difficult for people who only know the syntax of native JS to understand what's going on. (To counter this - a lot of projects that are written in CoffeeScript are bundled with the compiled JS code as well - which also happens to be very readable IMHO).
3. (biggest problem IMO): debugging in CS sucks right now. It would be a no-problem with SourceMap though, so we have to endure it just a few more months.
I hear this a lot, but seriously, have you ever had any real problems with debugging CS? The output is clear enough for anyone to know exactly where to go for the error.
It's a pain, still. I don't generate js files. When something like that happens, I have to go back to command-line, type 'coffee ...coffee', open generated js file and see where the problem was.
That's your problem right there ;) When you're using CoffeeScript, you're absolutely supposed to generate all of your JS files. -- For the same reason why you don't run all of your JavaScript via eval() while you're developing.
OK then. I have already 7-8 tabs in my terminal open all the time (a few for servers, some for redis, some for mongod, some for vi, some for other tools, some for debugging, etc.), so I guess another tab wouldn't hurt (I'm not a fan of running processes in the background).
1. JavaScript isn't a very readable language. (I think this is untrue. I've seen some incredibly well written / structured JS) 2. Not everyone knows CoffeeScript, so when you put a project up on GitHub and it's written in CoffeeScript, it's difficult for people who only know the syntax of native JS to understand what's going on. (To counter this - a lot of projects that are written in CoffeeScript are bundled with the compiled JS code as well - which also happens to be very readable IMHO).