Recently at Zivtech we started migrating our base theme for Drupal called Bearskin over to a gulp-based CSS compiling system. Up until now we had been using the original Sass, written in Ruby, but lately it's been feeling a bit slow.
So you write a lot of CSS, right? I used to be like you. I'll bet you probably write enough CSS to see tons of possibilities in the code, but also maybe you pull your hair out over some of the limitations?