I still find the Mobius to be insanely good for positional accuracy in pure stereo, beats any combination of DT770/GSP600/K712pro/HD700 connected to NuAudio/GSX1000/XonarEssence. Sure, there is an audible hiss when they are quiet. They get hot. They push on the ears slightly (even with gel pads). Don't get me wrong, I find both GSX and SBX to be better at VSS... Just talking positional audio and imaging for FPS here.
No idea how good/bad their support is. Their software/driver design leaves something to be desired, but I'm guessing they have a limited team for it.
Positional accuracy for stereo is pretty much meaningless, imho, unless one is palying left-to-right scrolling 2D games. Stereo only contains left/right position and IF game engine calculates it, distance and reverbation.
The whole point of VSS is to get the discrete 7.1 sound probably via HRTF into a surround-like experience, where front/back localization is retained. Hopefully in the future, this will include audio-tracing the soundwaves in the game geometry.
That is the *ONLY* way to retain proper positional accuracy, beyond mere left/right panning.
Of course, if the game-engine (Like Overwatch) has it's bult in VSS (Dolby Atmos), then a stereo only headset/soundcard will do fine, but it is still Discret multi-channel via VSS algo (game engine provide) into a stereo headphone.
But in the end, we are comparing the actual algorithms (WavesNX, Dolby Atmos, SBX Pro, Sennheiser GSX algo, Nahimic 3D, etc) against each other, regardless of the headphone itself (yes, the headphone does affect this, but it can only decrease the quality of the positioning that the VSS algo gives out).
And running VSS from a stereo input (2-channel discrete) makes no sense for game positional accuracy, it just mucks everything up.