After receiving my 8kx half an hour ago i want to share my first impressions, too:
Setup was easy and straight forward. Tried first Fallout 4 VR with the 5k+ on a DAS to compare then directly after swapping. Comfort Kit played out nicely. Also my packeage did not contain the thinner face foam, so the lightbleed from the cutouts for the glasses are a bit distracting at first, but thankfully not having a lightsource behind myself was beneficial for my experience.
The audio was barely hearable. Even after cranking up the volume to 100%. I think i need to use a booster or my vive in ears in future.
I swapped the 5k+ with the 8kx and paired the controllers. then i strapped on the 8kx and…well… still saw screendoor in the white pimax logo. and chromatic aberation at its borders, too. Hmm. Then i checked the IPD and suprise, it was set to 69.5 automaticly??? Must be pure luck? Or software adopted my setting of the 5k+, but hardware setting was different, still showing my IPD in the HMD? I don´t know.
Destortions are better than in my 5k+. But it is definately there. Maybe i can improve it with dialing in my IPD better with software, etc. I am waiting for @SweViver s NewPimaxExperience. If i look at a vertical beam structure in FO4VR everything is fine. If i turn my head to the right/left, the more i do, the more that vertical beam bends in the middle outward (barrel distortion) - not a lot, but visible. If i look with one eye/lens centered then the more i go to the middle of the lens, the more it bends inward. So the more you go to the outer edge of the lens it bends outward, the more you go to the inner lens area it bends inward. Again, very likely gone with thinner facepad or more accurately dialed in position/aligment in software.
Chromatic Aberation is also still there. I had the SteamVR-Performance-Window active in my lower viewing area (standard position). And on its borders you can clearly see the blue/yellowish colors at the border of that overlay.
Sweetspot is similar to my 5k+. I think that is the biggest disapointment. Not that its pimax fault. Just that i thought they could improve that with using the sdame lenses - silly me.
Overall despite this all sounds disappointing because i was nitpicking on some known issues, THIS HEADSET IS FREAKING AWSOMELY SHARP and i can´t wait to test it more thourougly with automobilista2 in my sim-rig (a shame i have my d-box system not setup yet)
Edit: colors are fine, brightness, too.