Yeah there is a nice review here in Polish but
Google translate does a good job of translating it into English and the results are what Rasmus says.
If viewing angles are your primary concern and you don't care about HDR and frankly most people do watch their TV's with the lights on then it's probably a good choice. Also makes an excellent gaming display so long as you avoid HDR.
It would be interesting to compare the SJ850 against the lower end 6xx and 7xx models to see if they are pretty much the same other than the various bells and whistles tacked on by LG or is their better care taken on the 8xx line for panel uniformity and other issues.
They along with the SJ800 use cheaper WRGB pixels structure which if you listen to online people is somehow a deal breaker but all it results in it text on screen might be a bit less sharp, not good for PC usage but again most people don't use TV's for reading text.
I hope Rasmus you could take a look at lower end models from LG as those are rarely looked at, AV enthusiast sites focus a bit too much on the high end for those with very deep pockets that many of us cannot afford.