This is very similar to Susy for Sass / Compass. The big benefit for me is not having to revisit the markup to change a class from grid_4 to grid_5 and such. Y

This is very similar to Susy for Sass / Compass. The big benefit for me is not having to revisit the markup to change a class from grid_4 to grid_5 and such. You just leave the markup as is, and all the work to change the layout stays in the style sheets, as it should be.