[EDIT] oh as for BeOS, it ran a lot of the same junk I ran on Linux just fine. Better, really. It wasn't suitable for a server, but that didn't and doesn't really matter for one's desktop OS experience. Especially these days—can it run a VM (as one supposes any modern BeOS-alike could, because why not)? Cool, then I can run most any deployment target I like on it.
Only Mandrake and PCLinuxOS got this right, they had nothing in /etc which wasn't applicable, because somehow generated programmatically by their installer, according to the choosen configuration.
That was CLEAN, there were no useless ##commented out things for stuff the system didn't even had installed.
Unfortunately their package repos at the time were 'clean' (meaning lacking the stuff i needed/wanted) too.
SUSE also tried this with YAST, but got it wrong often, and felt sluggish and bloated.
I can't really remember XFree86 and later Xorg crashing on me, except when pushing its boundaries wrt multi monitor and hotplugging, i guess that depends on the used hardware and the quality of their drivers?
Regarding the shitty hardware...
The f-ing fastest desktop experience i ever had was somewhere in the late days of KDE 3, across NetBSD, ArchLinux and Gentoo, on Pentium3@933Mhz with 512MB RAM, onboard I815 Intel graphics(edit: with the 'superspecial' 4MB VRAM Dimm-thingy), and some IBM Deathstars. With the same toned down look across all three systems, and toolkits, instead of the usual teletubbyfication.
What can i say? When your KDE 3 crashed you were holding it wrong, or it was somehow miscompiled, be it the optimization , or some libraries.
For me it was rock solid and lightingly fast, at least in my configurations.
The same can be seen nowadays with systemd and pulseaudio. They can be used if configured right. The question is if one wants to be hassled with that, if it isn't.
/endrant