The LG UF6800 UHD TV uses a less accurate 4k pixel structure known as RGBW. While it does have the correct number of pixels, it is missing some colored sub-pixels. Most people won't see the difference, though. Apart from this issue, it is an average LG LED TV.
For most people, the fact that the LG UF6800 is using the less accurate 4k panel structure RGBW won't be a big deal. It is hard to tell the difference when watching normal content, even when sitting close. The bigger issues are the average-high input lag (for gaming), the poor contrast (for movies in a dark room) and the significant amount of reflection (in a bright room). At leas, it is able to maintain good color saturation off-axis.
The LG UF6800 LED TV looks like most other LG TVs of 2015. It has a wide stand, which could be a limitation if you have a small table.
The LG UF6800 has an IPS panel, like most other LG TVs. The contrast ratio is low, and in line with most other IPS TVs.
The gray uniformity is average. The edges are darker, and you can see a few horizontal whiter bands on the screen, but nothing outrageous.
The best thing about this TV is its color accuracy at an angle, due to its IPS panel. Note that while the colors remain fine, the blacks don't (especially at a vertical angle).
Update 01/06/2017: We have changed the methodology of testing. Since this is an old TV which we don't have anymore, we extrapolated the results from 2016 TVs.
For an IPS TV, the blacks are more uniform than average, but every small defect is amplified, due to the poor blacks.
There is a slight loss of detail on very sharp text on native 4k content. This isn't an issue for movies, but it is noticeable when the TV is being used as a PC monitor. More details can be found here.
Direct reflections have a rainbow around them.
The luminosity is very limited. Also, when exposed to a lot of light, the screen has a yellow tint.
The motion blur is average. It shouldn't be an issue for sports, but it is not ideal for gaming.Note: Due to the very aggressive PWM even at 100% backlight, our response time measurement is less accurate on this TV.
It supports a 24p input signal without issues. However, if it is sent over 60p or 60i, it can't reliably do the reverse 3:2 pulldown. It is a 60Hz TV, but it also has the optional soap opera effect, which you can turn on via 'TruMotion'. That feature won't look as smooth as on a 120Hz TV, though.
The input lag is average-high, and could cause some issues for some gamers. The good news is that, as long as you have 'TruMotion' off, it doesn't matter which mode you are in to get that input lag.
It doesn't support gaming at 120 fps. It does display chroma 4:4:4 at 4k and 60Hz if you turn on 'HDMI Ultra Color' and label the input as PC. However, the text still won't be 100% clear because it is not a 'full' 4k TV. More details here
Decent low-end for a TV, but the frequency response and loudness are poor. Pumping may also be present under heavy load.
Good and even distortion results across all volumes, but the TV doesn't get loud.
This LG is a smart TV, and it comes with the latest WebOS, which is great. It only has a very basic remote, though, so it is not as easy to navigate as on the other LG TVs. It also has a more limited number of inputs.
You can read our overview of LG's WebOS here.