The only thing that will prevent me to buy a Sony TV is Android TV. I have bought a nVidia Shield and quickly replaced it with an Apple TV.
This is by far the least reliable OS ever. Plus it's awfully slow to boot.
It's a goddamn shame as Sony engineers can make fantastic OS (the Vita's one is still the best console OS ever made to me with the Switch, and the PS4 one is good too), and my old Sony LCD 40W4000 still looks better PQ wise than most TV I see everywhere, and I never had a single bug with it.
New Sony TVs use a faster processor and also use the more efficient Android Oreo.
Yea, the new X1 Ultimate Processor is real snappy when using Android on the new Sony. I have no experience with the older line models(my last TV was a Sony X850B from 2014-15 I think. Pre-Android with a proprietary Sony OS, but it kind of sucked. Sluggish, convoluted, its own GUI with a bunch of tiles that felt disorganized).
I know Android gets a lot of hate, but the Sony OS prior wasn't exactly better in any way before. Though it wasn't the cross-media bar or the elegant PS4 minimalism(It's like the different biz segments have zero communication). It was just another bunch of app tiles haphazardly thrown on screen against a color backdrop with a million icons and drill menus you need to constantly wait to load in to perform some quick toggles or basic functions.
The new Android setup on my X950G is light years better. Super fast, no lag when navigating, almost instant load of apps. And the Settings quick menu is nice and a single button press away, unlike my old Sony OS which had like 5-6 clicks just to get to the thing I needed.
Only issue is that some apps kind of crash or have weird quirks at times. Like Netflix will drop audio entirely with my soundbar, some people experience similar hangups. HBO Go crashes when I try to FF or Rewind a stream pretty regularly after a pause. Many argue its an Android issue that Google needs to fix, but they are minor and have quick simple fixes when it occurs. But still...Android probs.