The Aero is 35 PPD, not 39. Anything that states 39 is fake as it's using supersampling and/or upscaling.
I personally don't see how the Aero is simracing Nirvana in the current market. Other than current highest PPD, it falls behind in both h.FOV and refresh rate plus lots of chromatic aberration and poor blacks (but mainly the h.FOV and refresh rate). I'm pretty sure Varjo fixed the bad barrel distortions otherwise add that to the list too.
I bought the Aero to replace my Reverb G2 but I had to send it back for the following reasons:
- motion blur while turning/moving head
- massive chromatic aberration
- serious edge distortion/warping (with new profile enabled)
- terrible stereo overlap, which caused an black spot between my eyes, something that I don't have with my G2. This is a way bigger issue then the low FoV
- impossible to use it with multiple people, because auto ipd gave much worse chromatic aberration than manual ipd so every time you switch from person to person you need to go to the software of varjo and you need to adjust all 4 hardware knobs, takes in total 10-15 minutes to get it perfect every single time. This while I can switch the G2 from face to face in a few seconds (just ipd slider)
- red colour was shifted
The blacks, the FoV(vertical was REALLY low) were also issues but the above points were the reasons for my return. I'm more happy with my G2. Even if the Aero was priced the same as the G2 then I would still go for the G2, because the Aero was simply unusable for me(mainly because of stereo overlap and what I described about "usage with friends").
Edit: but I don't agree with your refresh rate point; 90hz is sufficient for sim racing. Even the 4090 cannot handle more than 90fps/Hz locked at high PPD/FoV with foveated rendering. If you want higher Hz then you need to lower the resolution which is not a good idea for sim racing, you really want as high as possible PPD and FoV, this combined with 90hz/fps. This is more important than Hz/refresh rate (as long as its 90hz, you're good).