Firefox 4 beta is is now available for public download in a move the Mozilla foundation says "it all begins here".
Representing the largest overall in the web browser's history, the new update has been described as a radical re-write of the underlying systems in order to achieve significantly boosted performance. Early reports of a much faster start up time address criticisms the Firefox had repeatedly faced in the past.
There's also the much-welcome browser tab "sandbox" functionality which means that just one tab will crash rather than the entire browser, a move that was widely welcomed when it was introduced with Google's Chrome browser. Also more than a little reminiscent of Chrome is the new tab design, repositioned up top.
There's many more improvements to be had including support for 64-bit operating systems, much improved bookmark handling, HTML 5 support (hot on the heals of the recently released Opera 10.6) and integration of Windows 7 Aero Peak support for a better visual consistency when running on the latest Microsoft OS.
The beta is equipped with a feedback button which pops up smiling and frowning face icons labelled with "Firefox made me happy/unhappy because..."
Unfortunately the new Firefox represents such a departure that previous third-party extensions will not work with the new version. Since the rich library of extensions have often been regarded as an ace in the hole for Firefox, it's likely that keen Firefox users will want to keep an older version handy until 4.0 compatible versions of their favourite extensions appear.
Firefox has struggled to improve its market share of web browser usage worldwide, particularly in the face of upstarts like Google's Chrome and Apple's Safari. Likely this has been a consequence of previous versions of the browser being viewed as overly cumbersome and slow, a comparison the lean and nippy arrivals have been keen to emphasise.
With Safari 5 and Opera 10.6 having recently been released, the browser marketplace is awash with high quality competition. The next version of Microsoft's browser, Internet Explorer 9, is still many months away and it's going to need to be very good indeed to make a good account of itself. At least among those who have the inclination to install a new browser.
To grab a copy, head over to the the Firefox 4 Beta download page.