I'm with crewmeal on this.
One of the Richer sounds branches in the South East has a habit of being honest.
They had their UHD tele demo set up to display the demo stuff. It looked brilliant. It looked like one could walk in to the picture.
They then showed us the tele with their regular TV signal. (No doubt boosted behind the scenes, some how)
It was good, but not as good as the demo. We did not buy the tele. We didn't have the money, anyway.
The other issue is price. Prices seem to be all over the place for tvs right now. If you do decide to buy, a salesman in John Lewis gave some good advice to a couple near me in the shop yesterday. He simply said decide what features you want, and ONLY buy those features. He thought some of the bells and whistles were being priced far too high.