Nearly as good as OLED. Just sadly not as good.

Yes if you can look beyond the serious light bleed issues it has and are watching 1080p or 4K content. Put Freeview on it and it looks like a 240p YouTube video.

I replaced my VT series 50" Panasonic plasma with the lower 55JU64000 model, My hand was forced due to my Plasma dying.
I was expecting to be disappointed but was surprised to find the picture on the new samsung LCD is better across all sources and the picture actually has a nice natural quality to it.

In my Currys they have the tv's plugged into their digital tv service (Freeview). On Sunday I was in my local store and on the same row they had the LG 49UF770v, the Samsung posted and the Sony KDL-50W8009C. In my opinion the Samsung had the worse picture viewing BBC1, channel 1. The LG was just marginally better and the clear winner on BBC1 SD was the Sony. The LG and Samsung just looked a little unfinished around the edges of people heads, bodies etc. On BBC1 HD, channel 101 the pictures were better obviously and nothing to choose between the LG and Samsung but the Sony was still better in my opinion. If 4k tv's are supposed to upscale 1080 channels there was definitely no evidence of this but as I notice my own tv's picture is better when using an external tuner via hdmi then perhaps the upscaling only works via hdmi and not via aerial or satellite input.

I was looking at purchasing either the LG 49UF850v or the Samsung UE50JU6800. My own tv is just under a year old and is an LG 50LB650v. Both these tv's cost £150.00 and £200.00 more than I paid for my tv yet the picture quality was no better and decided not to buy. The picture quality on both tv's were no better than the LG 50LF561v which was in the aisle in front of these. Not 4k but at £499.00 as good a picture for a lot less money.

I decided not to buy anything in the end. The Sony was the best picture easily on SD and slightly better on HD when viewing channels 101, 102, 103 and 104. Manufacturer's are very clever at creating the right videos to put on usb and stick in the back of the tv but viewing from about 8 feet away there wasn't any difference I could see between the 1080 tv's and the 4k ones. Eventually most screens will be 4k but more pixels doesn't necessarily mean a better image.

Yeah I also saw this in some owners forums...
Trying to decide what to got for, ideally want 60" but some good looking 4k 55" deals

Philips 55PUT6400 - £629 @ Argos - Cheapest, Android, ok reviews, no extended warranty

Samsung 55JU6800 - £799 @ JL - Seems very good value, cant really find direct review, question over 55" screen compared to 50" and 60", 5 year warranty

LG 55UF850V - £850 @ Currys - Seems a good spec, good review, 5 year warranty

Fed up of looking at TVs...

According to the European model sold in Holland then panel in the 50" is made by CHE MEI (Innolux) and the 55" made by BOE. No Samsung or Sharp panels are listed for these tv's sold in Holland. This is something that purchasers should not be put off by. If you like the tv then buy it. Just because it has a Samsung panel in it does not mean its going to be better. It may have brighter colours or better contrast but it is how it appears to the user that matters most along with how the panel copes with movement etc and reliability. I had a samsung panel fail at under 2 years. I have a CHE Mei panel in one of our LG's and it's a lovely picture.

Also rumour has it that the 50" is only a 60Hz panel. I have no evidence of this as technical reviewers don't appear to want to tell you. Perhaps they are slightly biased but looking at the models on rtings.com it would appear that the only 100Hz tv's in the 6000 Samsung range were the curved ones.