Things will look better... by quite a margin actually
I'm absolutely loving the Index, just can’t stop racing and marveling at the graphics. But like everyone, what impresses me most is the improved audio. I didn't know I was missing out on audio details and body with my CV1, I can now hear soft turbo's better, I can hear what my tires are doing better, it's like going from cassette to CD! The first time I went off track and caught some dirt/stones in my wheel wells, I could hear them so clearly I thought my rig was loosing screws or so
Engines have much more depth to them. I can hear the wind whistling past the car at high speed with such clarity.
Index screen/optics: It's better than my Rift CV1 of course. I only have experience with my Rift CV1, my Vive and Vive with GearVR mod.
SDE: on the Index I can still see it, but only when looking for it, not like on Rift CV1 or Vive where it's a constant overlay on everything. I was expecting to not see it at all, but this was too much to ask for, I guess only Reverb can really defeat SDE. But it's no longer an obvious hindrance, as long as you just forget about it you won't actually be reminded by it. With my CV1 I always saw it, wherever I look, there was a real fly stopper door in front of my face! With the Index it's just a slight 'sharpness' of the world which disappears when you start enjoying VR.
Colors: nice colors, cooler than Rift CV1 and less saturated, less bright than Vive, but fairly natural I'd say.
Blacks: Havent played any space games so can only comment on sim racing: I can't see any difference with my busted old Rift CV1 (which if anything had some serious grey smear anyway), Vive does still seem better here, but this needs more testing.
FOV: a lot bigger than Rift CV1 (I had VRCover super thin). With my Rift CV1 I cannot see my left mirror when looking straight ahead (in the Alfa Romeo Giulia Quadrifoglio), with the Index I can see it completely. I have the eye relief turned in so far that I can't see the edges of the screen, this is maybe 2 degrees less than fully pressed against my eye balls. My Vive with VRCover 6mm also feels slightly smaller.. but I need to do the TestHMD FOV test to objectively measure this. I think it's because of the high quality optics that there is a better awareness of the world. And it's very well calibrated, there is no warping or distortion, the whole screen feels natural to the eyes. I'd say the Index is big enough for me, it will bode me through to the next generation (StarVR?).
Edit, did a test:
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Rift CV1 (VRCover super thin)
VFOV: 114°
HFOV: 84°
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Vive (stock lenses, VRCover 6mm):
VFOV: 126°
HFOV: 98°
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Index:
VFOV: 130°
HFOV: 108°
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Clarity: using the reading test in TestHMD with the Index I can clearly read the whole oval arrangement at a distance of 5 meter, all words are completely sharp and readable evenly. With the Rift CV1 I can clearly read it at 3.25 meters, but the edge words are a bit blurry. HTC Vive (original lenses) at 3.5 meters, but the edge words are very blurry. For info, it's this test:
Eye Box: it's definitely bigger than Rift CV1 and Vive, but not as big as I was hoping. It's not corner to corner, there's still a large portion blurry at the sides. I'd say the 'eye box' is about double the size of the CV1. I can identify cars in my left mirror and inside without moving my head. With CV1 I couldn't even see the mirror. Good enough for me.
Hertz: at the moment I've found 90Hz and SS 130% to work best for me (Titan X Pascal, 6850K). With 120Hz I needed to lower SS all the way down to 80%. Or at 100% but with lowered MSAA from 4x to 2x and shadows and reflections down two steps. With 120Hz, looking out to the side, objects and curbs flying by are definitely smoother, less choppy. The whole world feels more solid, I feel more like driving a real car as opposed to watching a movie of driving a car. This has given me the taste, now I really want the 2080Ti
Actually, I'd go so far as to say, don't buy the Index if you're not prepared to buy the 2080Ti and 9900K.
God rays: no god rays, absolutely none for me. Also, I don't see anything like fresnel rings, it's an absolutely clear optic, kudos to Valve.
But.. I do see the kind of flares that people talk about, in the far corners of my vision when there is a high brightness area in an otherwise low brightness scenery. It's not in any way a hindrance or disturbing, but it's something I could do without. These flares would be in the absolute lower corner of the screen if the sky is bright on a dark cockpit. This flare then blurs the contrast of the lower cockpit and moves around when you move your head. This is something new that I haven't experienced with any other HMD and people have been complaining about it, some even stating they will return their Index because it's a deal breaker. For me it's fine, it's really the only thing reminding me I'm looking through glass and not directly into the racing game
I guess there's always a compromise somewhere.
Stereo overlap: I can see they are canted, but the whole middle part of the screen is overlapped, only the outer left and right edges are not overlapped, but this is in the area that is blurred anyway, so actually looking there with your eyes doesn't make sense anyway. I guess they chose a bit more peripheral awareness without compromising stereo vision, it's a good balance, I'm glad they did.
Build quality: it feels like a Glock. It feels like a Mercedes. It smells like a new car. Very, very solid, no play in any parts, no flappy stuff, no squeaking, no rattling, no cheap materials. It's executive class build. This thing feels like it will outlast a few VR generations, far beyond where anyone still needs it.
All in all, it's a keeper for me. Next gen GPU/CPU will help me SS up and maybe hit 144Hz soon, this will definitely carry me on until next gen HMD's become mainstream.