So this is my quick run-down of Pros/Cons versus the Index:
1. Clarity: Obviously the Aero blows the Index away here. Although with the Aero I really cannot see individual pixels, I can still see vertical rows of the pixel structure. So not perfect.
2. God rays: Pretty bad on the Index, none on the Aero.
3. Distortion: Holy smokes a lot of barrel distortion in the Aero. Maybe not as noticeable in flight sims, but really bad in standing/FPS games like Alyx. The Index has a little bit of warping, but almost unnoticeable compared to the Aero's distortion.
4. Smoothness. The Index blows the Aero away here. 144 Hz on the Index and it's smooth as glass. The Aero at only 90 Hz starts at a deficit, and yet there is still some stuttering that I cannot solve. Even in the Varjo Base software, not even in SteamVR I get this stutter. It's super annoying, and if I cannot get it solved with Varjo support, I'm afraid it's heading back. NO way should a RTX 3090 running a VR headset with basically nothing going on in a loading room be stuttering. And I've tried just about every combination of Varjo Base settings to no avail.
5. Fan: Pro is that it helps keep your face a little cooler but con is it's definitely audible with the Aero.
6. Colors: Aero wrecks the Index here. I've always thought the Index looked washed out, but ya the Aero colors pop quite a bit more.
7. Contrast/blacks: Both suck. Non FALD LCD sucks. Grey blacks and poor contrast on both. Really need a OLED. I'll also be looking into the new Panasonic MeganeX.
8. Comfort. Both to me seems to be about equal.
9. Sound. I use IEM on both, so tie.
10. IPD adjustment: Aero's automatic is cool if you have different people trying the headset. But if you are basically the only one that uses it, kind of a waste. You can manually set the IDP in the software, but every time you turn on the head-set, it moves the lenses. Kind of pointless, as it just wears out those motors more for no reason. I prefer the set-it and forget-it slider of the Index.
11. Field of View: Horizontal; they are about the same. Both leave some to be desired. Vertical, the Index crushes the Aero. When I first put on the Aero, I was kinda taken-aback by how small the "view portal" of the world is.
12. Chromatic aberrations. I really really hate you. Aero has a ton of it. Index just a small bit. Basically as much as the god rays in the Index piss me off, the Chromatic Aberrations in the Aero take their place.
13. Usability. With the Aero, you have to manually unplug the headset to turn it off. You also have to manually unplug your base stations to turn them off. There is no Bluetooth communication between the Aero and the base stations for power management like there is on the Index. The Index also powers itself off after you close down SteamVR. I know, super advanced!
So I am pretty torn. There are a lot of tradeoffs with the Aero. In order to get that great clarity, good colors and no god-rays, you have to put up with narrower FOV, Chromatic Aberrations everywhere, only 90 Hz (and with stutter for me, TBD), the same poor blacks and contrast as every other LCD HMD, and barrel distortion out the Wazhoo. For $2,000. I think I am on the fence on returning the Aero, using the Index a bit more until the MeganeX comes out. If I cannot get the stuttering resolved, it's 100% going back. Too me that is too distracting.