Associate
So you've literally viewed them both in a shop, that's hardly a good comparison as you don't know how they have been set up, I'll take lots of professional reviews over seeing a couple of TV's in a shop.
I compared them in person and using online reviews. RTings rates the X90J a 8.2 Vs the C1 an 8.8. Not a huge difference. Most reviews have the X90J being equally rated or only slightly lower.
The X90J outperforms the C1 on both SDR and HDR brightness which is very apparent when you compare the two in person. It is also brighter in game mode. Seeing as I hardly ever watch content in pitch black conditions, the extra brightness makes the X90J look better, in my opinion, when viewing in my normal conditions.
The X90J is pre calibrated way better out of the box than the C1. No need for an expensive professional calibrator to come out to make the colours look the way they should. That is probably another reason I think the X90J looked better in person.
Even after calibration, the colours on the X90J are more accurate according to Rtings.
The X90J also outperforms the C1 on Colour volume, gradients, lack of stutter and sound quality.
Android OS is also superior in my opinion to what LG uses.
Then you factor in the zero risk of burn in and the much bigger screen size for less money, it becomes a bit of a no brainer.
People should do their own research and go see the TV's in person but to dismiss the X90J just because it's not OLED would be a mistake.