I don't particularly like all of the syntax choices in CoffeeScript, and I absolutely don't subscribe to the theory that fewer keystrokes means cleaner code, but on anything complex I think CoffeeScript is a better choice than vanilla JavaScript.

It really is true that having a compiler make it impossible to screw up your scope saves you from a lot of mistakes. This feature is probably the thing I wish we had put in Objective-J most. It's also really nice to have a syntax for classes.