The highest display resolution of the UE40JU6440 is 4K Ultra HD. That's over four times the display resolution of the most frequently found HD type of Full HD. 4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
A 4K Ultra HD HD type is in fact the best display resolution amongst all similar spec TVs that have been around for around the same time as the UE40JU6440.
The worst display resolution amongst similar types of TV is HD Ready.
4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
We compared this TV to all the other 4K Ultra HD TVs and we think the Panasonic TX-48CXW404 (£459.62), the Samsung UE40JU6465, and the LG 49UF7767 (£1,059.77) which is cheaper is also worth considering.