I'm also waiting impatiently for Pimax to launch the 8k.
It's just three weeks ago that I got my second 4k, and I am so glad with it, compared with the Rift I re-tested once again in June.
Yes, of course, Positional Tracking, OLED displays and 90 Hz might be of avantage - but that SDE is just so bad and annoying...
Last but not least, Pimax is really improving its product: With my first Pimax begin of this year and its drivers at that time, Euro Truck Simulator 2 didn't want to start in SteamVR, or at least, one had to tune some complicated work-arounds with the RiftOverride and so on.
Now, just a couple of months later, my second Pimax with the up-to-date drivers is working out-of-the-box with ETS2!
Furthermore, in the same time, Steam improved SteamVR and added that SS-resolution slider, and that positive impact on the Pimax' 4k screen is massive! Finally, I am able to detect the bends in Project Cars from a distance I wasn't before without that slider, and in ETS2, I finally can read all the signs which wasn't possible before, although that 4k Display and even when being right next to a sign. (And honestly: I cannot imagine how some pro's can drive for record times in Project Cars with the Rift or the Vive given that aweful Resolution... how do they see anything...?!? I would crash into every second bend...
)
So I really can't wait for the 8k version with 200° FOV. Hopefully it gets a DisplayPort instead of HDMI... 8k, 200° and 90 Hz ...
(PS: My first Pimax didn't broke - I simply sold it since I didn't use it for a couple of months and thought I might not need it anymore. Mistake...