Some of the main features of Firefox 4 are:
New JS values: Changes to the C++ representation of JavaScript values allow Firefox to execute heavy, numeric code more efficiently, resulting in cleaner graphics and a better browsing experience.
Starts faster: Firefox starts up even faster thanks to XPCOM module improvements that pave the way to a better extensions framework.
HTML5 Support: A new HTML5 parser and full support for web video, audio, drag & drop, and file handling means Firefox 4 is ready to run the best web apps of both today and tomorrow.
Direct2D Hardware Graphics Acceleration (Windows only): Experience super-fast graphics acceleration with Direct2D, now enabled by default, on DirectX 10 supported hardware.
Web Console: With this experimental analysis tool for modern sites, Firefox allows you to peek under the hood of dynamic web pages.
Multi-touch Support: Firefox now integrates multi-touch support for Windows 7, enabling you to interact with your browser in a whole new way.
Protecting Your Privacy: Firefox puts your privacy first, fixing flaws in some web standards that allow bad guys to snoop around and expose your browser history.
and much more…
Try it, coz its worth trying. Click the button below to download it.