That's probably mostly it. Plan 9 doesn't really have that much in terms of features. It's greatest strength is in how they go together. Having everything as a

That's probably mostly it. Plan 9 doesn't really have that much in terms of features. It's greatest strength is in how they go together. Having everything as a file is about the only thing I can think of that unixes don't have (which is the most important, yet not initially clearly how, feature). Oh, and on the programming end maybe the simplified api and CSP based threads/concurrency library.