OTOH, without LESS a lot of us would have to add Ruby to our stack :p

I use SassC: https://github.com/sass/sassc - a basic SASS/SCSS compiler written purely in C. It's not 100% up-to-date with the ruby version and you miss out on the more advanced features like custom functions, but it's blazing fast and I've never really needed more than the basic features anyway.

My problem there is that Susy Grid requires bleeding-edge SASS. And the very latest Compass version, too.

> The libsass library is not currently at feature parity with the 3.2 Ruby Gem that most Sass users will use, and has little-to-no support for 3.3 syntax.

That said, it is mostly good enough. I've used it for a few SASS projects in combination with Bourbon and it works great. IMO the huge compilation speedup (I saw reductions from 5-6s to about 200ms) was worth the slight move backwards in features. I became much more productive with a more responsive livereload.

Libsass is missing some hugely important features, but it (appears to be) in very active development and the disparity list is shrinking.

Even lacking missing those features, the 12x compilation speed improvement in libsass is pretty compelling.

The note is slightly outdated - the recently released libsass V3[1] is targeting SASS 3.4, and they expect to fully pass the spec by V3.1

Does libsass work 100% with the Bootstrap sass port? Every time I've checked on libsass support it is behind the ruby version in some way.

Yes - we use libsass across the board, including building BS3, and have had no issues with compatibility. It used to have a problem with high precision numeric values (like "6.666666666%" in BS) but that's has been resolved.

There is a Sass port of bootstrap that is labelled 'official' and is in the same github project as the 'canonical' less version:

https://github.com/twbs/bootstrap-sass

It's already got a 3.3.0 available, it is kept sync'd.

I have very occasionally run into a bug or problem with the sass port not being kept properly parallel to the original less, but mostly it just works fine.

Just tried creating a Compass project with bootstrap-sass 3.3.0, ran into this problem:

https://github.com/twbs/bootstrap-sass/pull/757

Releasing the LESS and Sass versions at the same time is a bit premature. Looks like the Sass version wasn't tested as much.

Yeah, I have run into that too previously, with "QA" on the Sass port not being as good as one might ideally like.

But, hey, look, they already released 3.3.0.1 of the sass version fixing the problem, 3 hours after the ticket was filed, that's pretty responsive, sometimes that's the most you can ask for.

(Part of the issue is it's not JUST a Sass version, people expect a Sass version that works with Compass with or without Rails, and that works with Rails without Compass, and that works with Sprockets without Rails, and that works standalone with nothing but Sass just compiling css like the Less version, and each context has it's own picadillos).

Less still appears to be significantly more popular than Sass (sources: github / npm stats, not perfect sources but likely directionally correct)

How much of that is due to Bootstrap though?

I dont,I prefer LESS over SASS for multiple reasons(running less in the browser during development is one).

Use a pre-compiler then. Gulp is so fast you won't even notice the compilation time.

Is there a secret I don't know about or do browsers convert LESS to CSS natively?

No, but there's a JS file that transforms your LESS into CSS in the browser. It's handy for development but obviously you'd want to pre-compile for production.

Is there any reason someone couldn't do the same thing for Sass?

The biggest issue is probably keeping up with Sass. Other Sass implementations are behind on features.

Less ... well, there's less to keep up with since there's one implementation of it that I'm aware of.

I used to prefer Sass, but mostly because it was the only thing going at the time, but I'm starting to lean toward Less.

looks plausible: http://medialize.github.io/sass.js/ :-)