Ease of Use:  

Firefox is well organized and intuitive. The browser has an easy–to–use interface that has all the essentials but isn’t cluttered. Firefox features are powerful and useful, yet simple. 

Firefox 3.5 has several additional features that further improve usability. A fully integrated spell checker allows users to work directly on the web and still have spelling errors checked.

Another great function is an automatic session restore. When Firefox reopens you pick up where you left off, even if the browser closed unexpectedly or by accident. It's really nice to not have to spend time getting back to where you were. Session restore restores text you were writing in an email and even downloads you might have been in the middle of.

The Firefox download manager is easy to use and integrates simply with the browser interface. The download manager gives you the ability to pause downloads and then pick up where you left off. This straightforward resume function is even available after a system restart.

Security:  

Finally, Firefox has integrated private browsing. With Firefox 3.5 you can easily enter and leave the private mode, browsing seamlessly in complete stealth. Furthermore, unlike other browser privacy modes, there is no noticeable icon or change to the interface in private mode.

Firefox protects against viruses, spyware, malware, phishing, and pop–ups. Firefox 3 has an integrated password manager, automated updates to help locate and fix security problems, and parental controls.

Another impressive browser security feature is the one-click site info. Simply click on the site in the location bar and you can view important safety information.

You can easily clear your personal information including history, cookies, passwords and web–form entries with the click of a button. New to version 3.5, you can even remove all traces of your visiting any specific site. Think of it as a selective private mode that can go back in time.