I second this recommendation, even for those not using Ruby! The Sass compiler is written in Ruby but that doesn't mean you have to know Ruby to use Sass.
If you can do without the latest of the latest in Sass I highly recommend using a libsass implementation. So much faster than the Ruby version!
OT: I also like that they've used a BEM-like approach, although I personally prefer a double underscore as separator between elements.
Libsass is night & day vs Ruby Sass. No problems using libsass with Bourbon, Bourbon thankfully stays away from the bleeding-edge features (many of which can be emulated with clever functions).
In a previous project, we saw Sass compiles go from ~15s to about 400ms by moving to libsass. Completely changes the development cycle (with HMR or livereload) as you see changes immediately.
I've been using node-sass (libsass wrapper) recently, which hasn't been too bad compared to less (which is native to node/js). Seems to be working fine with bootstrap-sass, and surprisingly fast, compared to less, so I imaging the ruby sass implementation would be similarly slow by comparison.
