Probably the most stable OS I’ve used was Sun Solaris which was based on Unix. Also the various Mac OS’s throughout the years. Windows NT also was stable and not limited by running “on top of” DOS. Still have old copies of NT 4.0 lying around.
The following may not be the most “technical” but is based on real experience. I ran Windows 2000 Professional for a couple of years before “XP” was released. It too performed well at least for me. It was aimed at “business” users instead of home. I got it by ordering it with a new computer. Probably “Windows 98” or “Me” were the least reliable. Windows 3.1 was fine as I remember (showing my age) although more of a “shell” than true OS. I unfortunately remember a bizarre “user interface” from the late 90’s called Microsoft Bob. Never used it but have seen it running on other computers. Widely considered one of the worst products Microsoft has offered.
“Vista” probably was the worst OS based on personal experience. I can remember purchasing the “Ultimate” version in 2007 with great expectations. And it looked great! Sadly it crashed frequently. Too frequently, necessitating powering off. Writing in my technology blog early 2008, I noted “five Windows Failures and 23 Disruptive Shutdowns since September 2007.” Came very close to switching to a Mac for my main PC at that time.
For a very successful company, Microsoft has made a few missteps over the years. The funniest one I think, was the use of “Start Me Up” by the Rolling Stones for the release of “Windows 95.” Someone in Marketing wasn’t paying attention... The idea of course was to promote the “simplicity” of the OS as well as the use of the “Start” button. But the lyrics paint a slightly different picture.
All my friends who worked in “IT” used to quote the following:
You make a grown man cry
You make a grown man cry
You make a grown man cry
But my personal favorite was
this one:
You, you make a dead man cum
You, you make a dead man cum
I can remember ordering the CD “Tattoo You” from Microsoft then listening to this.

So someone HAD to know what they said.
Sorry for such a long post. Hope some will enjoy it.