TL;DR: I definitevely don't have anything against Bourbon, and we can actually use it with Compass (Bourbon for most CSS3 and Compass for utilities, spriting, compilation & other functions). But not using Compass is missing a big advantage Sass has over LESS.
- Doesn't work with libsass (yet — I read they plan on supporting libsass, probably later this year)
- needs Ruby (for now), and installs the
chunky_pnggem - Slow compilation (because parsing image sizes, assembling sprites… actually takes time)