I work for a company that means we have a few 4k TVs kicking around. They look amazing. It’s a combination of the resolution, and also the colour depth (10 bits/colour component instead of 8bits).
There’s not a huge amount of 4k content around at the moment, but there will be.
A 4k Netflix account is £9/month, which seems pretty reasonable. So my next TV will be 4k.
And they’re not much more expensive, because it turns out that dead pixels on a 4k display are much harder to see than dead pixels on a 1080p display.
EDIT: that chart doesn’t appear to mention the colour depth improvement, so is pointless.