The highest display resolution of the Samsung UE48JU6550 is 4K Ultra HD. That's over four times the display resolution of a Full HD TV, which is the most frequently found display resolution. 4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
This TV's display resolution (4K Ultra HD) is in fact the best display resolution across all similar spec televisions that have been around for a comparable time to the UE48JU6550.
An HD Ready HD type is the worst display resolution across similar types of TV.
4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
There are a number of other 4K Ultra HD TVs currently available that you might also want to look at including cheaper TVs such as the UE48JU6075, or the UE48JU6580 both from Samsung or the Panasonic TX-49CX740.