I'm a huge fan of Sass. In fact I taught myself web development with Sass/Bones, so writing in pure CSS makes me feel kind of like a caveman making a fire. I 'get' why Sass and other preprocessors will make my life easy. I don't 'get' why a postprocessor will make my life easy...
I use Sass with postprocessors. They are not enemies. Sass and preprocessors are better to fix CSS syntax. Postprocessors are better for some automatically task, like autoprefixing, media queries packing, polyfills, etc.
Unfortunately, Sass is not so flexible as JS. Even simple things require a lot of code. And a lot of task is just impossible on Sass (for example, Autoprefixer, RTLCSS).
