Given there is just one month to go until the official Ubuntu 17.04 "Zesty Zapus" release and past the ordinary freezes and nearly at the final development milestones, I decided to take a test drive this morning of Unity 8 with Mir atop the latest daily Zesty packages.
With Ubuntu 17.04, Unity 7 with the X.Org Server remains the default desktop environment, but Unity 8 and Mir can be found on the default ISO and it's just a matter of logging out and into the experimental Unity 8 session. It's really easy to try out for those interested. For my tests today I was using an Intel Xeon box with a Radeon RX 470 graphics card atop Ubuntu 17.04's default Mesa packages and kernel. Overall it was an interesting experience and while a lot of bugs remain, the Unity 8 experience was much better than the last time I tried it a few months ago and is almost up to being usable for a daily Linux desktop.
The first thing you may notice are the pictures in this article rather than proper screenshots... That's bug #1. When hitting the screenshot key on the keyboard, the system would immediately become unresponsive. When trying to pull up the screenshot utility under Mir, it wasn't working. Thus for this article and when testing these latest daily Ubuntu Zesty packages, I resorted to taking pictures of the display.
The second issue I encountered was either botched 4K/HiDPI support or some combination of Unity8/Mir not liking the Radeon RX 470 paired with this particular display. The rendering was all botched using these latest packages -- there weren't any of these display problems when making use of Unity 7 + X.Org nor have I encountered any other similar display problems with this card/monitor on other distributions. Even when switching to a VT after launching Mir, the display was still garbled. So I resorted to connecting the system to a 2560 x 1440 display. When doing so with this alternative monitor, the mode was properly set and there weren't any display problems.
With those two main issues out of the way, onward to the working Unity 8 experience.