Not sure how many have tried this. If so, what is your opinion?

It works well in my Win10 x64 :

The drum sounds and guitar sounds seem nicer in DOOM... (compared to Sound Canvas VA)... maybe it's just me...

http://veg.by/en/projects/syxg50/

VEG wrote:

A software MIDI synthesizer for Windows, which functions as a VSTi plugin. Supports both the Yamaha XG and the Roland GS extensions, which is a unique feature of the S-YXG50. It is based on the trial version from the Yamaha SOL2 package. The full version of this VSTi had never been released, because Yamaha had decided to discontinue support of all its software synthesizers in 2003. Fortunately, the trial version have a full version of the S-YXG50 engine, so it is possible to remove the trial restrictions to get a full version. In addition to the removed trial restrictions this patch adds the portability (installation and registry keys are not needed), also it uses embedded into the DLL resources the 4MB official wavetable files, which is the best version of wavetable files for the S-YXG50.

How to use […]
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How to use

You have to set up some VST host to play MIDI using this synth. It can be your favorite player, but you need to find a plugin, which allows to play MIDI files through VSTi. Some instructions are provided below. Use the bi2_polkovnik.mid (35KB) for checking your setup, it have to sound exactly as the bi2_polkovnik_syxg50.ogg (2.0MB).
VST MIDI Driver (as a system MIDI synth)

VST MIDI Driver allows to use any VSTi as a global system MIDI synth. In this case every game or MIDI player, which uses the default system MIDI synth, will use Yamaha S-YXG50.

Download and install the VST MIDI Driver from this page.
Copy the syxg50.dll from the yamaha_syxg50_vsti.7z into any directory.
Open VST MIDI Driver settings, click “Load VSTi” button and choose syxg50.dll.
In the Advanced tab choose “VST MIDI synth” as the default MIDI synth.
Ready! Now Yamaha S-YXG50 VSTi will be used as the default system MIDI synth.