1. RISC OS is still the best OS. The latest RISC OS version is open source and runs on modern ARM hardware, while seamlessly running apps from 1987, despite changing several companies and being forked.
2. It was designed by a trans girl, Sophie Wilson.
3. RISC OS is the next best thing after the Lisp OS. Yet if you port SBCL to ARM, then it will be the best thing.
4. Can run on the cheapest laptops, phones and under $100 pi400 computers at high speed.
5. Beside lovely userspace, a much better kernel design than Linux. No DLL hell, no dependency hell. Sophie Wilson solved it all in 1987.