Personally, I think that if 1% of the resources that have gone into various Unixes had gone into either of these systems, the outcome would have been far superior.
Plan 9 started as an off-shoot of Research Unix and in some ways it is the raw, unfiltered Unix ideal, along the way influenced from work done at PARC and ETH Zurich. By and large the GNU/Linux community seems to be drifting away from Unix as far as possible.
Genera certainly sets a bar for a single-user workstation.
https://en.wikipedia.org/wiki/Genera_%28operating_system%29
Personally, I think that if 1% of the resources that have gone into various Unixes had gone into either of these systems, the outcome would have been far superior.