Firefox 4 Beta 1 is now available for Windows, Mac OS X and Linux. We were expecting it last week, as Mozilla had initially estimated the first beta would be available in June, but it’s here now. This release is for the adventurous only — it’s the first beta so it’s stable enough, but not rock-solid. So, if you’re eager to get an early peek at the next generation of Firefox.

The thing that probably matters most to everyday users is speed, and after using it for an hour or so, I can report that Firefox 4 is noticeably much faster than the various 3.x builds on my desktop.

Page load times are speeding up substantially across all the browsers now — Chrome and Safari recently received upgrades with hefty speed boosts, the new Opera 10.6 is on par with those releases, and the new Microsoft IE 9, due later this year, is also showing off some impressive speed in its current release, Platform Preview 3. Speed is one area where Firefox has recently drawn low marks, with some users switching to Chrome simply because it’s so nimble. But Firefox 4 appears set to change that when the final version arrives in a few months.

First, there’s a new look for Windows users. Tabs are now on top by default (a la Chrome). Mac and Linux users will get this feature as a default in subsequent betas. If you want to try it now, just go to View > Toolbars > Tabs on Top to enable it. Windows users, you can switch the option off using the same method if it’s not your thing. Also new for Windows people is the orange “Firefox” button in the top left. Click it and you get a dropdown filled with the most popular application menu items.

The other new feature — and this is for all OSes — is an integrated Feedback button next to the search box. Click it to report anything that Firefox did to “make you happy” or “make you sad” (Mozilla’s actual wording). The Feedback system incorporates the Test Pilot add-on from Mozilla Labs to collect and anonymize the feedback.

Courtesy by webmonkey.com