Compared to Ubuntu 12.04 Beta 1 from the beginning of the month, there's a new kernel that's derived from the Linux 3.2.12 upstream release, improvements to the desktop with the new Ubuntu HUD, LibreOffice 3.5.1, and a new control panel for Ubuntu One.
On the server side, Ubuntu 12.04 Beta 2 carries OpenStack Essex RC1, Zentyal and OpenMPI 1.5 are now available for ARM in Universe, and there's KVM 1.0 on x86 with nested KVM support by default (e.g. cloud-in-cloud).
Other features of Ubuntu 12.04 Beta 2 are talked about in the release announcement along with the obvious download links.
If you missed it, out this week are some old hardware thoughts for the Precise Pangolin as well as mixed boot performance results. More test results are coming soon.
Ubuntu 12.04 LTS is expected for release on 26 April.