Iam very impressed. Cable TV / low quality content is maybe more suitable on Sony TVs because of the better upscaling / image processing, but in all other areas the C9 is just superior (well it should be for the price).
LGs trumotion surprised me, its pretty good. Soccer for example looks for me as good as on Sony TVs with their motionflow.
WebOS is just sooooo much better than android, its really well thought out and fast. Gamingwise, its unfair to compare, because 7-13ms + VRR + great HDR + perfect blacks is just a different ballpark.
Btw, dolby vision on the Sony X900F was often just too dark, for example "The Haunting of Hill House" or "Sabrina". My first impression of these series on the C9 was like "wtf, this looks so right now". So i guess Sony is still fucking up something in terms of DV.
Last but not least, i won the panel lottery. The Panel of my 65C9 is sublime, i do not see any banding, DSE, dead pixels in any content i have watched so far. I hope it will last long.