Thank you for the detailed reply Dalto.
The curve has it's "cool" factor but I don't think its necessary, in fact this may sound strange but when I looked at the 55" version of both the JS8500/X850C, the Samsung looked smaller? optical illusion haha
I view most of my blurays in a dark room, so I'd be setting the TV for low light viewing, from the rtings review the Sony has 3800:1 contrast? Which I believe is good. Is the samsungs Local dimming that dramatically better (£800 better, gets brighter for HDR but £800 better?), or only in certain situations?
Knowing the price difference, I'm starting to think I'd be a fool to get the JS8500, based on their small differences and common specifications as stated in your post and below to re-iterate.
HDMI 2.0 x4
and yes £800 difference...
I realise this is a thread for the Sony TV in question, however something else that is driving my decision is that I'm literally just £300 away from having the pennies to buy the Sony...