Mozilla hopes that the beta 12 release would be the final beta and can release candidate soon. "This Firefox 4 Beta is considered to be stable and safe to use for daily web browsing, though the features and content may change before the final product release," Mozilla said in the release note.
New Features in Firefox 4 Beta 12 release:
* Increased performance while viewing Flash content.
* Improved plugin compatibility with hardware acceleration enabled.
* Hovering over links now displays the URL at the bottom of the window rather than in the location bar.
* General stability, performance, and compatibility improvements.
With the beta releases, Mozilla aims to eradicate the bugs and other high priority problems before the final candidate release.