Despite their share of problems (the author explained what's wrong with CoffeScript in his opinion), languages compiled to JS will keep flourishing unless some future ESx will turn it into a more conventional language. Even in that case, being the native language of the "internet virtual machine", people wanting to use a language-X-look-alike for the front end will keep designing their transpilers.
In my case I never considered CoffeScript because of the indentation/semantic spaces thing. I had to work with those languages sometimes and the troubles I had when moving blocks of code around and copy/pasting examples from the net have been enough to undo any gains from a cleaner syntax (assuming it is cleaner). No Python either here, obviously, nor HAML or SLIM for templating. Irony: they've been invented in the Ruby community which somewhat prides itself of using a language with a better syntax than Python (I second that, Python looks too much like a C with defs which is maybe the reason for its success: familiarity.)
My main gripe with significant white space is that it forces a specific level of formatting that is generally less attractive and readable then what I would otherwise use.
Please elaborate. Usually, significant whitespace only forces code at the same nesting level to have the same indentation, it doesn't specify what that indentation should be.
I dislike significant whitespaces because when there's a lot of code that has multiple nesting levels it becomes a bit hard to follow. I like it when my code has a beginning and and ending token ({ and } in JS/C/C++ or `begin` and `end` in Ruby). Whilst writing CS I found myself writing `# end` a lot.
Also, not to mention (maybe my editor lacks this feature) I like using ^M to jump from end to beginning braces of blocks, and I can't seem to do that in CS.
However, all of these arguments just boil down to "this is my personal preference"
In my case I never considered CoffeScript because of the indentation/semantic spaces thing. I had to work with those languages sometimes and the troubles I had when moving blocks of code around and copy/pasting examples from the net have been enough to undo any gains from a cleaner syntax (assuming it is cleaner). No Python either here, obviously, nor HAML or SLIM for templating. Irony: they've been invented in the Ruby community which somewhat prides itself of using a language with a better syntax than Python (I second that, Python looks too much like a C with defs which is maybe the reason for its success: familiarity.)