mozillalinks

Mozilla has successfully reached the beta milestone in its new Rapid Release Cycle strategy that aims release new Firefox versions about every 18 weeks, instead of uncertain feature-oriented, when-it-is-done approach used in the past, that while it has worked ok in the past, is too slow for today web development speed with a lot of vectors acting at the same time including mobile, web standards, hardware acceleration, desktop integration, as well as the traditional ones: security, usability, customization, and performance.
While Firefox 5 beta comes with no less than 1053 bug fixes it also does with the shortest new features list compared to any other Firefox release to date:

1. A more polished user interface with shorter shadows and sharper borders in all elements.
2. Performance improvements allow Firefox 5 to be 9% faster in the SunSpider test than Firefox 4.
3. Comes with support for CSS Animations, part of the CSS3 specification that lets web designers define animations between styling attribute changes. Still in development, CSS Animations are declared with the -moz prefix.
4. The option to enable the Do Not Track header for web servers has been moved to the Privacypage in the Options dialog.

An important difference in this update is that while add-ons are usually broken for most of a beta lifetime, in this case, Mozilla has automatically bumped compatibility for most add-ons, as there is no API change, so most of them should work right now with the beta.
Get Firefox 5 Beta, available for Windows, Mac OS X, Linux, and Android from Firefox Channels page.