Assuming that no fatal bugs emerge, this version (minus minor bugs) will soon be released as a final product that is up to six times faster than its predecessors, features a new minimalist interface and incorporates long-awaited sync and panorama features.
Whether you decide to download the release version or wait for the final release, here's a quick overview of the new features to expect.
1. Tabs Are On Top
As with Opera and Chrome, Firefox 4 tabs are placed by default above the search bar instead of below it.
Alex Faaborg, the principal designer on Firefox, created a
See an in-depth explanation of the decision here.
http://blog.mozilla.com/faaborg/2010/06/24/why-tabs-are-on-top-in-firefox-4/" target="_blank">video to explain the thought behind this decision. The advantages of doing so, he says, are more logical visuals, space efficiency, and accommodation of new features like app tabs and a redesigned notification window that associates the notification with its site's tab.
2. App Tabs
Mozilla 4 allows you to turn any tab into an "App Tab" by right-clicking on it and selecting "Pin as App Tab."
These tabs stay put in the upper left-hand corner of the browser even as you scroll through your other tabs, which prevents the web applications you return to frequently from getting lost.
When there's an update on one of the app tab pages, like a new e-mail, Facebook message or Twitter update, the tab glows -- rather classy compared to the bouncing, flashing alternatives.
3. Switch to a Tab Via the Search Bar
Start typing the address of a website that is already open in a tab, and Firefox 4 will suggest an option to switch to that tab, even when it's in a different open window. If you're someone who opens more tabs than you can remember, this feature can help prevent repeats.
4. Sync Across Multiple Devices
The ability to sync bookmarks, browsing history, passwords, form fill data, and open tabs across multiple computers and smartphone is built in to Firefox 4.
While similar features have been default in Chrome and Opera for a while, Firefox director of engineering Johnathan Nightingale says that the organization took the time to develop "weapons-grade encryption."
5. Panorama
Panorama (formerly tab candy) now allows you to overview all of your tabs and organize them into groups using a drag and drop interface.