I used DSSSL straight out of college. It wasn't the parens. Scheme just takes time to wrap your mind around and it seems so opaque when you are coming from the world of C and Java as I was. I was incredibly intimidated by it, and so were my fellow programmers. We used it and it worked, but no one felt that they fully understood it under the hood.
CSS is just so dead simple in comparison. Classic example of worse is better IMO.