I have had the 55XE9005 2 weeks, before this I have used KS7000, XD93, LG B6, hopefully this is helpful to some people :
#1 There is no obvious stuttering on any source SD, 1080p, 1080i, 4k etc. smooth motion without SOE, if you use 2 on "clearness" there is almost no motion blur. Overall motion on XE90 is very good, from the Rtings reviews it is possibly better than XE93 and ZD9.
#2 Sony upscaling, noise reduction, "reality creation" works very well, most brands you are better turning that stuff off because it looks worse. Reality creation approx 20/100, RNR : off, DNR : auto, smooth graduation : low-med, does a very good job with low quality sources, compared to OLED for example which is covered in grain, noise, posterisation etc. 1080p and 4k look very good, SD looks as good as possible on a 55".
#3 Input lag, 4k 60hz 4:4:4 with BFI with 33ms lag, this is very good as most TV's will add lag when you try to use 4:4:4 or BFI, most TV's do not have BFI option in game mode.
KS7000 - The XE90 is pretty much better in every way compared to the KS7000, the KS7000 is good value, if you do not notice the PWM double image, stuttering, SOE, poor local dimming etc.
XD93 - The samsung panel in the XE90 is much better and higher contrast, dimming is better, input lag is fixed, android and menus are faster.
LG B6 - The XE90 cannot match the blacks and contrast or the dolby vision HDR, BUT, the motion on the LG OLED is not good, this is the big problem with LG OLED, also the B6 makes a mess out of any low bitrate, low resolution, grain etc. and the full screen brightness is poor compared to LCD.
I use a philips bias light and replaced the stand, the stand is quite high and leans backwards, which makes the viewing angles a problem. With the new stand and the bias light it looks very good. The uniformity is very good, a bit darker at the top, other than that it has no DSE or banding, almost no backlight bleed.
The dimming works well, a bit of "blooming" but the other 99% of the time it looks very good, it can go from a very bright to dark, as I said before looks 10x better with a bias light and you have to sit DIRECTLY infront of it, the viewing angles are not great. Overall I would say this is a very good effort from Sony!