Just starting to work with Shopify theme editor and the first thing I've looked for was options to use Sass.
Im glad it is supported, but a bit disappointed by it's limited support. Personally I don't need all the bells and whistles from Sass, actually I use libsass locally for compilation, but the possibility to have partials is quite essential to my current workflow.
Currently im considering have my regular Sass structure outside of the assets folder, and just compile into a regular css file which will then get exported to the platform. Have to try if this works, would love to hear if anyone have tried this.
Edit: Just noticed Rodrigo's post above, which im now going through.