How to install Ubuntu on the Raspberry Pi 3?
Only Light weight Linux/Ubuntu distro will work for the Raspberry Pi. Ubuntu it self is too heavy and will cause you Pi to lag real bad. Ubuntu Mate is a Officle flavor of Ubuntu. That means when Ubuntu gets updates Ubuntu Mate gets updates. Ubuntu Mate is the only Ubuntu that works best for the Raspberry Pi. F.Y.I, If you plan to use Ubuntu Mate, please use a class 10 or better SD card, otherwise you might get horrible lag. Hope this helps!