VcXsrv is a open source project under GPLv3 license about building reliable X Server using Visual Studio in potentially optimal manner. It's common knowledge Microsoft Compilers are very good for Windows platform, since there are free variants it's tempting option. It was my first choice for X Server when J'ai essayé Windows Subsystem for Linux for the first time in Windows 10.
Xming is a weird project which under term Donation hides a price for the installable binaries. J'ai toujours though donations are voluntary, but it seems the author has different perception. This project was the only option to have X Server on Windows natively for very long time, but since we have VcXsrv, there is choice.
Personnellement, j'ai have very good experience with VcXsrc, it's easy to install and works very fast. I'm surprised it's not more popular. As far as Je sais their code is more clean version of original X server and doesn't relate to Cygwin.
