Power Tools For The Web
First of all, I take no credit for this what-so-ever. I just needed to use Susy 2.x (not Susy 3.x as it has no mixins), and wanted to change it to work with SASS instead of NODE-SASS, which is now does...
Susy-sass is an agnostic set of tools for creating powerful, custom layouts. We provide the language, but you provide all the opinions.
Use a grid, don't use a grid, or use a combination of grids — it's all up to you.
We didn't want to build another system, we wanted to build power tools that you could use in any system.