Asm/C and Java/scala are unfair comparisons, since they're totally different languages with different structures and idioms.
I just started using CoffeeScript for a project of mine and while it did clean up the messy look of the Javascript, it doesn't improve much upon Javascript feature-wise. I felt like I was still writing Javascript, it just looked a little better.
I've been writing CoffeScript daily for about 4 weeks now. On the first day, it seemed pretty minor. About three days in I was a believer. Now, when I write the occasional few lines of Javascript in my browser's console, it just feels so arduous to type. Whenever I pop open a Javascript library to read it, I feel like there is an assault on my eyes. I'm never going back.
It looks a LOT better, it requires a LOT less typing, and it saves you a LOT of stupid syntax errors and typos compared to brace-semicolon-comma-parentheses stew.
I just started using CoffeeScript for a project of mine and while it did clean up the messy look of the Javascript, it doesn't improve much upon Javascript feature-wise. I felt like I was still writing Javascript, it just looked a little better.