So I installed Manjaro as my Desktop's only operating system several months ago and have been enjoying it (and KDE) since then without too much drama. But it's a “rolling distro”, meaning that it updates all its components all the time (instead of only releasing security fixes regularly and then going for a 'big-bang' new version once or twice a year). This has not caused me too much grief, to be honest: there was an update months ago that rendered my ZFS disks inaccessible, but only for a day or two and I could live with it, as I was getting merry in Riga at the time.
But just after Christmas, either an update too far happened or (more likely, if I'm being honest) I installed something new and untested and my entire O/S, at the next reboot, refused to boot into graphical mode. It instead parked itself into command-line-only mode… and even that was rendered impossible to use because the command line would auto-dim to the point of illegibility about 10 seconds after coming up. I could switch the monitor off and on and the command line would be normal brightness and usable again… for another 10 seconds! After that, 'dim, switch off monitor, switch on monitor and type fast' became the order of the day.
My backup scripts were functioning entirely normally, so the “operating system” as such was just fine; but the graphical stack was borked. I once managed to get a message saying 'KWin was unstable' but that didn't help me much!
Which is all a bit of shame, as I was having such a good time with Manjaro (an Arch-based distro) that I was contemplating writing an article about how to install it and configure it as a desktop for the general user. If I could put my finger on what I installed, tweaked or otherwise contributed to the breakage, I wouldn't mind so much: blame me, not the distro, basically. But as I can't think of any likely suspects, I shall think rather the less of the distro instead!
On a spare laptop, I therefore installed Ubuntu 18.10 with it's Gnome desktop (instead of the monstrosity that was Unity!). It's new, it's reportedly sexy and Gnome is allegedly getting pretty good these days as a Desktop Environment (DE). But it was horrible. Really, really horrible! I had it installed for three hours before deciding that it was irritating me to the point of irrationality!
So I had another go and installed Ubuntu Mate 18.10. It's still Ubuntu, but with a default Mate DE, which is sort-of like the old Gnome 2 desktop (or can be made to look like it with a bit of tweaking). It felt sane, it behaved predictably, all my essential software was readily available and I decided to take the plunge and re-install my main Desktop PC with it.
Fortunately, my Manjaro installation had used separate mountpoints for /home, /root, /boot and some other stuff: since a fresh O/S installation only involves wiping /boot and /root, my old documents and program settings were preserved and I was thus up-and-running with the new distro in only an hour or so, with all the stuff I care about kept safe and sound throughout.
Not a brilliant start to the New Year, therefore -but a lot less painful than it otherwise could have been