Chris Coyier (writing at CSS-Tricks) with a detailed feature-for-feature comparison of LESS and Sass. (There’s also a useful, albeit short comment about how Stylus stacks up.) Very handy for someone trying to decide which to use in their stack.
Chris Coyier writing at CSS-Tricks about Sass and other CSS preprocessors. It’s a fairly long post, but it’s good to see someone taking the time and care to write something as thorough and even-handed as this.