But which "one single system" would you choose? If the answer is platform X, you put off the users of platform Y and Z. For different reasons in each case! Re

But which "one single system" would you choose? If the answer is platform X, you put off the users of platform Y and Z. For different reasons in each case! Really: try substituting Linux, Mac, Windows for any of X, Y or Z and then work it through. If you can't make the document for each system, I think it's probably better to document it as this more messy reality. I maintain documentation for a niche cross-platform product. I ended up going with the 3x solution.