The upside of having a system like SASS is that it can be a lot smarter about the underlying system it's generating content for, which you don't get if you use

The upside of having a system like SASS is that it can be a lot smarter about the underlying system it's generating content for, which you don't get if you use a general-purpose template system. Selector nesting in SASS is a good example of this. It makes both the styling and page structure a lot easier to understand, which is a bigger win in my book than the typing it saves. I see a system like Zen Coding not for tackling the same tasks as a template system, where the bulk of your work effort might be spent. It's for the irritating little bits around the edges where, instead of taking 5 minutes per page bashing out boilerplate, it now takes 30 seconds. Not a huge win, but a win nonetheless.