I guarantee that 4k gsync will not come anywhere close to the oled
IMO, £1350-1500 is a fair price considering you are getting the absolute best IQ there is, proper HDR too unlike all these fake HDR panels floating about in the monitor market.
You can do 120HZ @ 1920x1080. I would get one just to try it out, gaming is pure bliss in terms of motion clarity, even at 60HZ, it is night and day compared to my 60HZ LCD monitor (which is very good for motion, at least for a 60HZ IPS monitor anyway) and 120HZ mode with 100+ FPS just makes the motion clarity + input lag even better.
Regarding sharpness, funny thing is despite my monitor having a far higher PPI than the TV in 1080P mode, the Tv still looks sharper than it, perks of:
- no matte anti glare finish
- infinite contrast ratio
- sitting further back
The main thing really is the contrast ratio and proper blacks, it makes such a drastic difference to the image.
Unless you badly need sync tech. and "must" have 1-3ms of input lag or/and can't fit 55", there is no reason not to consider one imo, especially if you are thinking of spending £1000 on a monitor already.
Burn in will only be a problem if you use it for browsing/windows/desktop usage and game every day for 8 hours straight or something like that.