I used to be in this school. It has some downsides. I'm now back to the twitter-bootstrap-many-classes-are-fine camp. * your css can still get large in large s

I used to be in this school. It has some downsides. I'm now back to the twitter-bootstrap-many-classes-are-fine camp. * your css can still get large in large sites. Even though you're not duplicating rules, you're still filling your rules up with lots of comma'd selectors. * IE8 and lower have selector limits of 4095, we hit this because we used @extend on a fairly large site and had to split our css up more * It creates more dissonance for developers that are comfortable applying ready made classes. Now they have to make up (sometimes it really is just making it up, there's no real semantic name) a class name for something, go to the sass file and add it. This is more steps than they need. * Many of these things can be cleaned up by good usage of partials or their equivalent on the DOM side. You should be DRYing that up too, so I can't say I relate to the author's concerns about changing DOM.