Ubuntu Xenial isn’t an officially supported operating system for the Raspberry Pi, but there are images available for both the Pi 2 and Pi 3 in Trusty and Xenial versions. I’ve found the Xenial image works quite well, but as I recently discovered the Bluetooth chip that is present on the Pi 3 isn’t detected at all out of the box. Getting it working turned out to be a bit of a mission.
I have just finished upgrading my main workstation at home (‘hactar’) from Ubuntu 15.10 ‘Wily’ to Ubuntu 16.04 ‘Xenial’ which, after 3 days of trying, turned out to be one of the most involved upgrades I have ever undertaken. At the end of the day this was because of a bug1 in the LVM2 package on Xenial, and was a bit challenging to fix without just nuking the system and starting again.