I have been dabbling with Haiku for the last eight years and I absolutely love it. I contributed to them during Google Code-in contest - the community is awesome.
The design and cohesivity of the environment is something I always dreamt of when on Linux... In the last couple of years, the community focused greatly on ports, and much more modern software is available - so more people could use it as a daily driver.
With a bit more of backing it could be as good or better than macOS as a common desktop OS (fun fact: Apple was in talks with Be founder to buy Be, so this could have happened!).
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