FWIW, I have Ubuntu 18.04.1 / MATE 1.20.1 running on an ODROID XU4 and it is MUCH smoother and faster than a MATE install I did on a Pi. Don’t get me wrong, I am a Pi user and in fact have built a major work-related printed-circuit board interface gizmo around the Pi that works great. However, the Korean-built XU4 is a much more capable small computer than the Pi and is what I use for my cheap home Linux machine. The ODROID community is smaller but very devoted. Worth a look.
Check out the direct Pi3-to-XU4 comparison graphs in the links below:
Here’s a drop-in, ready -to-burn Bionic Beaver disk image for the XU4: