It's tough to run 12.04 on osx. In virtualbox, I can't get usb or mounting raw images to work, which is probably a virtualbox problem. On the hard disk, I can't get the bluetooth to connect any of the mouse, trackpad or keyboard. And, there appears to still be big bugs on Xorg, since it's a bit slow to boot up and there's no ubuntu animation during the boot, just a dark screen. Also, I couldn't get hole disk encryption to successfully boot, and I couldn't even get the user home directory encryption to work on the installer.

But, at least now, grub-efi works well with my imac 2011 with lion osx. But, grub-efi is not part of the installer, and to install it I had chroot into ubuntu from the live cd, then apt-get install grub-efi, then execute grub-install, then manually copy /boot/grub/grub.efi to a mounted /dev/sda1 EFI partition under the name /mnt/EFI/BOOT/BOOTX64.EFI. Then I blessed this EFI directory under osx, and it boots first and is usable. I'm even surprised that the bluetooth keyboard can up/down arrow and enter key work in the grub screen. So, this is a great improvement in running without rEFIt, which I couldn't get to work on osx lion.

I hope either Virtualbox on osx improves, or the Bluez and Xorg bugs get fixed so I can get more use of it. Right now, I just run a virtualbox 12.04 as a print sharer, since ubuntu can share printers to Apple's airprint, while osx still can't.

I also tried Arch Linux and Debian Testing, but couldn't get either to successfully boot, after the install. Arch Boot and the Arch stable-net-install both had bugs that dropped me to a busy box on first boot, and Debian booted to a frozen black screen. For all the problems with 12.04, at least it's installable, but on it's first boot, it took forever, which was fixed after installing the first updates and rebooting.