I am excited to get my hands on the 8KX and see how it compares to my Vive-1 in flightsims especially.
It might actually be effective for virtual desktop use as well now and will be a big step up for me in the ppd department but I am worried that the color and black levels will look like ass coming from OLED.
The valve index seems to have nicer looking colours but the pixels are larger and FoV is significantly less. still the gap between the pixels looks fairly low.
The one big advantage the index has is the higher panel refresh of around 120Hz or so which would be easy to notice.
On the 8KX I get around 170 degrees hFoV paired with a higher pixel density the biggest trade-off being that the panel refresh is currently 75Hz and might be bumped up to 90.
Index should be easier to drive since the panel resolution is lower but hitting max refresh would be difficult as well.
On the 8KX hitting 4K per eye native at 75Hz is very taxing but I could still switch on the upscaler turning it into an 8K+ basically.

I need to do a lot of experimentation and see what works best until hardware that is powerful enough to drive it to its full potential is available. I hope that the eye tracking solution module will be effective with foveated rendering.

I've read some comments from flightsimmers stating that ppd is more important to them than FoV.
With the 8KX I can get the best of both, but I am curious what people would favor for flight sims when the tradeoff is between FoV and refresh rate.

With high FoV I don't have to turn my neck as much and can notice moving objects at the edge of my vision even if it is distorted.
For higher refresh rate though it would be easier to judge how fast your approach is when landing/air refueling or lining up for a shot.

I am torn, additional situational awareness from FoV and better perception of speed from frame rate are both important.
Still the high refresh won't mean squat if you can't hit it and putting in filler frames in between renders.