I'm guessing someone who prefers SASS over SCSS is going to also prefer SASS over LESS.
One of the reasons we did not switch from HAML/SASS/SCSS to LESS/Jade/Stylus is the output. HAML and its cousins do the extra little things to help developers diagnose problems like adding comments with the original line # and file; pretty-printing, etc. All these options can be disabled for production of course.