Hi, I just bought the European equivalent 75xf9005 (I live in Germany) and I am no expert on panels.
However I know a thing or two about software, and sampling through the 166 pages here I didn't find any discussion on that (I understand it is not strictly audio/video, but it is part of the TV we own).
My take on this TV is that the image, motion and upscaling look great but SW is abysmal.
Here are the most annoying things (most can be found already around, but you can gather all of them only once you hit them personally).
1-power consumption: besides many functionalities walking up the TV continuously that somehow can be disabled, there seem to be no way to stop Google calling home in standby. That brings transitions from 0,5W to 20W all over the place. I am worried about the life of the power supply. I do not want to touch my wall mounted monster to replace that.
2-I use vpn. Nice that I can do that on the TV directly. Too bad that there is a long known bug that does the following. If you go in standby connected to vpn, next time you turn on, the TV crashes and reboots.
3-satellite channels management. Short story : buggy interface, you don't know what you are scanning, especially if you have 2 satellites on the same cable. Scanning doesn't go through most of the times. Channels can be managed (meaningfully sort of) only through PC.
4-Amazon prime : happy to finally have 4K content visible and a single remote without going to an external device? Yeah, if you don't mind extreme stuttering and broken app unable to change to original language.
5-search integration across apps? Nope
7-thousands of fully working android apps? Not exactly, android tv is the crippled sibling.
The fact that such a great panel shows a grainy crappy image in its menu page tells a lot about Sony's car for SW details.