Stu’s compiled a great list of resources for LESS users (like me) who need to use, or want to switch (Blah. Blah. LESS. Sass. Sass. LESS. Blah. Blah.) to using Sass.
Personally, I love LESS. But the real kicker is that I’m trialling a soon-to-be-released compiler that compiles Sass but not LESS, and it doesn’t play nicely with Codekit. That alone could persuade me to make the move to Sass. (For God’s sake don’t tell Jina Bolton that.)