I doubt VC will invest in a Foundation: there is no way to get their money back...

To be complete, if all goes well flex-wrap will be in Firefox 28 (unprefixed). It is in Nightly and Aurora.

CSS Grid implementation will start in 2014. A dev has been assigned to it, but I don't know where it stands in its work pile (quite high though). But plans can be changed, so beware...

Correct, but unfortunately, WebKit (and Safari) has not and introduced lately (read: this quarter) new properties with prefixes.

Regarding the amount of files (CSS +JS) loaded. We will minimize this when we will remove the old theme, which is still there, behind the scenes.

Could you open a bug the next time it happens (with a link to the page)? It would help in diagnosing the problem (client-side, server-side, doc missing, ...)

It is not yet ready. Expected for Fx 28 (but would not sign it with my blood). There is a UX Nightly with Australis (the name of the redesign) out there.

Really looking forward to it. Maybe it makes me sound superficial but that might be what finally makes me switch back from Chrome - the compactness of the Chrome UI is great. Firefox on OSX is really in need of a boost.

I don't know how well it works on a OS X, but I have been using the firefox-ux nightly build on Windows for awhile now. You can find them at [0]. It's been as stable for me as the other nightly builds tend to be, which is very stable, but do be aware that going this route can lead to running into bugs. I understand why these things take a long time to shake out, but it is massively disappointing to hear that the new UI won't be released until Firefox 28 or later!

[0] https://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/late...

I've been using UX Nightly on OS X as my primary personal browser for something like 6 months now and it has given me very little trouble.

It's worked well on Linux, too, but I haven't used it there as much.

It is a (long, hard) work in progress. One dev started this huge task about 3 weeks ago :-)

I hope this didn't come across like an impatient rant. I just wish them a quick path toward advancing state of the art ideas about DOM rendering and parallelism.

The page is up-to-date.

You should fill a bug with a demo in http://bugzilla.mozilla.org (with timing in Fx and in a Webkit browser to show the problem)

They won't read you here.

Firefox implements it without prefix (it is finalized). It will be enabled by default in Fx 20. It supports both horizontal and vertical flexboxes but not yet multiline flexbox.

Opera supports it fully and without prefix too.

Webkit tends to be (very) late in unprefixing (they are the only ones with prefix for Animation, Gradients, Transitions nowadays.)