It is better compare by yourself and decide as different people different preferable.
For me this Panasonic is very great on up-scaling STD contents. It is very well done. The only cons I can said is they is a very slight light border shadow on this EX600 model.
Sony X70E - It is nice but far more expensive and not running Android TV like others Sony this year TV, only start from X80E is Smart TV running Android TV OS.
Samsung MU6100 - I never like low end Samsung TV as it was not good.
LG UJ630 - I love LG new design remote which is very easier for input. LG WebOS design also much appealing. I initial is intend to buy LG TV. Support 2 out of 3 HDR format (HDR10 and HLG). The Smart OS is WebOS.
Panasonic EX600 - End up I choosing this and no regret. Just the only cons part to me is that very slight light border shadow. Support 2 out of 3 HDR format (HDR10 and HLG), website only mentioned support multiple format and I already test it confirmed is support HDR10 and HLG. The Smart OS is Firefox OS (now already purchase by Panasonic).
They is 3 HDR format in market. HDR10, Dolby Vision and HLG. HDR10 is the very common format and now all HDR TV is support it, awesome output quality, UHD Blu-ray is on this HDR10 format. Dolby Vision as I know only the LG OLED TV support it, so far as I know only Apple TV HDR is on this format even though it is the best ever did. HLG is the selected format for broadcast.
You can get a lot HDR sample to test here -
http://4kmedia.org/