The first beta release of upcoming Ubuntu Quantal is out. This release is mostly aimed for beta testers who want to try the upcoming release and report bugs before the final release is out. As being a testing version, its not recommended for regular users.
Some of the major updates in this release is the Linux 3.5 kernel, web apps, better Ubuntu 3d integration and unity previews. As most apps have been compiled in the latest gcc 4.7, users will experience significant improvements in overall performance of apps.
You can download the beta from here. Kubuntu and Lubuntu beta releases are also available.
Warning: On systems with an ATI Radeon 9200 graphics card the system will boot to a black screen. As a work around edit the kernel command line in the boot loader and add "nomodeset". (725580)
LibreOffice menus are missing when ran in non-Unity session (1044657)