Ubuntu distributions didn't always come with the latest GRUB, but Ubuntu 14.04 LTS (Trusty Tahr) might implement the most recent version, GRUB 2.02 Beta 2.
Canonical doesn't usually pick packages that are still in the Beta stages, but it might make an exception for the GRUB 2.02, which represents a year and a half of fixes and new features.
“I'd like to upgrade to GRUB 2.02 for trusty; it's currently in beta. This represents a year and a half of upstream development, and contains many new features.”
“Obviously I want to be very careful with substantial upgrades to the default boot loader. So, I've put this in trusty-proposed, and filed bugs.launchpad.net/ubuntu/+source/grub2/+bug/1269992 to ensure that it doesn't reach trusty proper until it's had a reasonable amount of manual testing,” said Colin Watson, the technical lead for the Ubuntu FoundationsTeam.
GRUB 2.02 Beta 2 does feature some pretty interesting stuff, like support for the experimental 64-bit ext2, better DM-RAID partition handling, TrueCrypt ISO loader, multiboot2 boot-services EFI specification, and tons more.