Now that I got my hands on an OLED Deck I have to say, people were overselling it as a display technology in my opinion. Everyone keeps jerking off OLED for how vibrant its colors are and how deep pure blacks are, but something that seems to be glossed over is how terrible OLED appears to be at handling greys... Maybe the Samsung panels are just particularly bad at it, but good lord, darker games all look like they have a permanent film grain filter slapped over them. I don't think my display is faulty either, tons of people are reporting the same observation. People with the LE model (BOE panel) are in turn reporting black smearing, although to a lesser degree.
Apparently it's called the mura effect and it's an inherent flaw of OLED. Although the intensity of the effect supposedly depends on the panel. I'm not sure Valve cheaped out again, or the niche that is small OLED panels simply has nothing better to offer as of now. In the end, the pros still outweigh the cons, but a straight upgrade it is not.