I bought a £2,000 Panasonic and I'm not happy with it, but it's regarded as one of the best all-round (DX902).
I think HDR is brilliant, don't get me wrong - looks great on both consoles, the way lights "pop" makes the biggest difference for me (especially in racing games, they look real). I'd definitely say 4K and HDR are worth getting.
But anything that's black (e.g. a player's hair in FIFA) leaves a trail as it moves around. Takes me back to the days of "ghosting" on analog TVs, it looks dreadful.
If £2,000 and (arguably) the best 4K/HDR telly you can get has a problem as glaring as that (and it's not a defect, it's present on every one of them), then something's not quite right with the technology at the moment...
I had a JS9000 briefly (absolute bargain for how good the TV was overall) but unfortunately there was a big red flickering line down one side of the screen when in game mode, and Samsung's response was "get the KS" - but the picture quality wasn't quite as good and I ended up going "whatever I buy, I want it to be perfect".
Hell of a backfire...