Maybe my mind is playing tricks on me because now PC Mode does seem more responsive. Check it out for yourself. I have a 2nd 23" TN panel that has about 35ms and my main monitor has 21ms. The F8000 actually seems in between this time compared to being almost neck and neck with my 35ms TN panel... If you're wondering how I test it, I basically just right click the desktop and you can see how fast the right click menu pops up.
Maybe that guy's readings were right... I'm going to download an actual timer to take a picture of instead of going just by eye. If it's literally gotten as low as that guy claims, I will be a happy camper!
So I did an actual input lag test and it appears the input lag has been fixed!
I used my tablet since it has the best (still crappy) camera on it compared to my other devices. It's a Surface RT BTW. More meant for skype calls, not photography.
F8000 on the left, Samsung s23a950d on the right. Consulting DisplayLag.com, the S23a950d has an input lag of 22ms. So the input lag for the F8000 appears to have been cut in half from the original 45ms. DisplayLag has the UN60F8000 at 45ms in their test. If my tablet's camera is correct it's now in the 20ms ball park because it is pretty much neck and neck with my 22ms Samsung monitor. Picture quality is rough in my picture, I turned the brightness on both displays all the way down and also got a lot of ambient light around the displays. Sorry for that, but the numbers are pretty clear I think.
I've never done an actual input lag test so if I did something wrong, tell me! But I think this is good proof that the input lag has actually improved!
For the record, that Vizio on top of my desk was given to me for free.