When comparing Plan 9 vs GNU+Linux, the Slant community recommends GNU+Linux for most people. In the question“What are the best Operating Systems for x86 PCs?” GNU+Linux is ranked 17th while Plan 9 is ranked 18th. The most important reason people chose GNU+Linux is:
It is a Unix clone.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Well designed
Plan 9's design is very orthogonal and well done.
Pro Designed to allow for multiple computers to work as if they were one
With Plan 9, computers are turned into terminals where you can access files and processing units which can be located elsewhere. Data storage is handled by another external server. This means that instead of each person having their own individual computer with all the required parts, all of the computing and storage is done in a central area and everything is networked in together.
Pro Unix-like
It is a Unix clone.
Pro Many different desktops to choose
Just use whatever you want. Some are lightweight, others are full of extravagant features. There is a flavor for each taste.
Pro GNU-userland
Uses the same userland as other GNU variants.
Pro Free
You don't have to pay anything.
Cons
Con Difficult to use software made for other systems
Plan 9 is very different from most other operating systems, and as such it's extremely difficult to bring in software designed for other operating systems ('porting').
Con No fully featured web browser
As indicated on the official Bell Labs webpage, there is no full featured web browser currently working on Plan 9, except abaco.
Con Not supported by most tools
Not supported by most dev tools beyond text editors.
Con GNU Copyleft
The coplyleft in the GNU licenses make it unattractive to many developers. It s also impossible to port GPLed Linux improvements to other more open operating systems like BSD or Haiku.
Con Frankenstein OS
The whole OS is mixed together with software from different sources.
Con Many distributions
There are just too many of them to know.
Con No interface Guidelines
Since there are plenty of X11-Desktop environments and two big Widget Toolkits, every app works and feels differently.
Con Most Distributions are not LSB-conform
The most Distributions don't follow the Linux Standard Base which results in different package formates, package management tools, bootloaders, init-systems or even filesystem hierarchy standards.
Con Often limited by decisions of the Kernel developers
Support for the latest features in Linux is often limited by their kernel developers, for example, Nvidia once had added patches to support Optimus on Linux, however, the kernel developers rejected those patches resulting in still no official Optimus support for Linux.
Con Most 3D drivers are not as fast as their Windows counterparts
The only display driver that comes close to their Windows counterpart is the nvidia driver. Both AMD and Intel drivers miss a Control Panel on Linux to adjust more settings than just your resolution they also usually much slower than their Windows counterparts.
Con Unix-like
It's only a clone and some things work differently.
Con A big mess
10-15 years ago I had everything working on my linux system bluetooth, graphic driver desktop etc.
Nowadays it is just a big mess: Distributions force me to use systemd a system I don't like since it is terrible to debug, KDE and GNOME(and its siblings) have moved even further away from each other no unlike years ago when they used freedesktop to unify things. There are now dozens of different GUI toolkits o choose every one with they own themes and usability(not to mention all the different minor versions like gtk2, 3,4 whatever that look and work all differently). in 2005 i could use bluetooth audio with alsa and no issues on every DE or WM nowadays you need pulseaudio to get it working some applications even need it to play audio. All distributions use different packaging formates (but they do and work all the same). You have now traditional apps and flatpaks, snaps and appimages. There are desktops/distributions that come with wayland preinstalled and the majority still uses X.org.
Con No graphical user-interface
As the most unix systems this also comes without a graphical user interface by default.
Con Not secure
Linux is actually the least secure OS and it is a security nightmare. Windows, MacOS, and ChromeOS are all far more secure.