I just wanted to update this thread, having created it almost 2 years ago now.
The conversation did turn to OLED TVs and I was very tempted, however after doing all the research I ended up buying a cheap 4k 43" TV to pair with my X34a just to see how I get on with it. I went for LG-43UJ630V for £330.
Pros:
- 4k image looks great quality
- Screen size is perfect for a small office environment
- HDR looks nice and this isn't even "proper" HDR
- Watching YouTube, Netflix, BT Sport etc is much better on the TV than the X34a
- Ultra HD from content providers looks really good
- Built in WiFi on the TV means apps are really convenient as opposed to browsers on PC
Cons:
- No Gsync - seriously, I don't think I can game without it now.
- 60Hz @ 4k - I just can't handle gaming lower than 70-80 FPS now.
- Desktop use - there's just no way I could use a TV as my main monitor
- Switching between primary display to game on the TV - it's a pain
- 16:9 resolution - it's fine for movies & TV but not for gaming or desktop use
I'm really glad I picked this TV up as it's priced really well and is a great addition to my setup, however I would have been gutted if I'd spent the money on OLED as the TV use is so limited in this environment.
I definitely don't want to move from Gsync, high refresh or Ultrawide for PC use so I'm still looking for an upgrade in the 21:9 100Hz+ space.