Using CSS Preprocessors prevent a lot of headaches and offer excellent benefits. One of the main problems that is prevented is so called "DRY" (Don't repeat yourself). CSS Preprocessors save time and provide valid CSS without breaking browser compatibility.
I've decided to write a different kind of article, asking web developers which CSS Preprocessors is preferred - LESS, SaSS or Stylus. Actually the original question was LESS vs SaSS, but few of them come up with an extra answer.
Additional reason, for writing this article is related to Google Trends and one infographic that I saw recently. Both provide controversial data, to what I have received from "real" web developers. The point of this article is not to compare syntax, flexibility, property lookup, functionality, etc... Obviously all are similar, though a bit different.
UX Designer & Web Developer
I use Sass, not a whiz on it but I definitely like it for variables, mixins and math - when deciding which to go for and start implementing into projects; it was a clear winner for me.
It's updated more frequently and has less issues than LESS and it's name isn't confusing. It handles math better and errors better, it's also a little more intuitive to use. Compass is awesome. But I can use LESS if it's packaged into a project, but personally I use Sass... Also their logo is awesome.
Sass. It's basically less 2.0
Stylus, sorry. (short answer, due to fact that original question was SaSS vs LeSS)
Love SASS. Also like to couple it with Compass to utilize the helpers compass brings to the table
If you still think, you can skip SASS, your projects just aren't big enough.
The research was done through Google Plus and Twitter. I am also running poll at our Webmaster's forum and will really appreciate, if you cast your vote - SaSS vs Less vs Stylus.
Of course your comment is highly appreciated, too!