I own one, and am really happy with it. There is some jank to expect though:
- The official system image is based on Debian Unstable. This means that you frequently get broken updates (for instance, currently waybar is broken, and just a few days ago, boot got broken by a buggy initramfs).
- At least for some SoMs there are also Debian Stable images available, which are, well, stable.
- I am running Gentoo on my Reform, and once one gets past the initial setup (kernel config is a challenge) it works pretty well. I have written a blog post about installing Gentoo on the Reform.
- DPMS off might not work reliably (depending on SoM). I got it working well on my BananaPi CM4 SoM by changing sway config though.
- Suspend-to-disk (hibernate) does currently not work. Last time I tried it, the system continued just fine, but froze a few seconds later.
- No clue if standby works. I don't use standby.
- Some other issues exist with the Banana Pi CM4, but there are workarounds: https://community.mnt.re/t/tracking-known-issues-and-solutions-with-the-bpi-a311d-upgrade
- There are probably more issues that I cannot remember right now.
That said: Now that I have Gentoo running on it, and found workarounds for the most annoying issues (except for the suspend-to-disk issue), I am loving the laptop and would not trade it for anything else.
I am curious how much work it will be to modify that Ubuntu image to fully work on the Reform. The audio chip and some other peripherals are on the mainboard, and need to be included in the device tree for the kernel to pick them up, so I would expect that at least some modifications of the image are needed.
It might already be enough to grab the device tree from the MNT gitlab, compile it, and put it in the boot partition for stuff to work. (You will likely also want to install the reform-tools - either from their gitlab or from their repository. They include a kernel module that is needed to get battery readout and to power off the laptop on shutdown.)
What helped me a lot while setting up the system was that I kept the SD card with the official (Debian Unstable) image around - every time something didn't work, I could boot it up and check how the official image does it.