I find the quality of javascript produced through coffeescript is much higher than devs who proclaim competency with javascript. Even the simple stuff (using closures properly, and '===')
I've found a lot of devs while they have been 'trained' in C/Java/Pyhon/Ruby have kind of just picked up bits and pieces of javascript without a really a firm understanding of how it works or it's idioms. Coffeescript on the other hand, has a very (python-esque) prescriptive set of idioms that produces very decent javascript, if you don't follow the idioms, it doesn't compile.
For an absolute "i know nothing" I think the Ruby, Rails, HAML, SASS, Coffescript is a smaller learning curve than ERB, CSS, Javascript.
I've found a lot of devs while they have been 'trained' in C/Java/Pyhon/Ruby have kind of just picked up bits and pieces of javascript without a really a firm understanding of how it works or it's idioms. Coffeescript on the other hand, has a very (python-esque) prescriptive set of idioms that produces very decent javascript, if you don't follow the idioms, it doesn't compile.
For an absolute "i know nothing" I think the Ruby, Rails, HAML, SASS, Coffescript is a smaller learning curve than ERB, CSS, Javascript.