Plan9 was far superior as a developer's system. It's text based tools are the best, bar none. But really it owes that to Project Oberon.
"Everything is a file" as an abstraction enables you to build really powerful through composition. e.g. running TCP/IP over a serial connection just by mounting files in certain places.
Your end user program doesn't need to know anything about networking, it just reads from files.
It's not perfect, of course, it had problems with throughput - we were forever discussing at conferences how to improve the protocol to implement streaming.
I describe it as a racing car, not everyone can drive it, you need to work to keep it going, you might kill yourself but when you're out front, it feels amazing.
I found during my ten years in Plan9 it was the most usable OS I have experienced in my 35 years of computing. My only problem with it is every other platform is now ruined because I gnash my teeth and say "would have been easy in Plan9".
https://www.telegraph.co.uk/news/2019/05/13/jeremy-kyle-take...