I like the human-readability that dashes lend to URLs, but there are two things that bother me about using them in this case:

1. A dash is an operator, which could get confusing when you are doing math. For example: (@grid-gutter-width * (@grid-columns - 1)).

2. As far as variables go... thisIsDoubleClickable, and_so_is_this, but-this-is-not. I suppose it's not the biggest deal in the world, but I really hate having to drag my mouse to select.

My two cents...