If I were asked this question, except as a piece of trivia exchange, I wouldn't want to work for them. There are arguments in favour of many OSes (including tho

If I were asked this question, except as a piece of trivia exchange, I wouldn't want to work for them. There are arguments in favour of many OSes (including those that I used in the long-ago past on long-forgotten iron), and many against those same systems. Using any OS is generally a trade-off; so if asked `what OS do you use?', I would answer `whatever is suitable for the problem and equipment at hand'. If asked `what is the best-designed OS you have ever seen', I'd instantly respond `Plan 9', which I have never actually used. As it so happens, I recently transitioned my daily driver laptop from Debian to Debian running under WSL2 on Windows. I had good reason for doing it. But I guess running that makes me a double loser.