richto:
It is a scientific fact that you have to sit closer than 6 foot from the screen at 50" screen size with 20:20 vision for your eyes to be able to resolve any difference between 720p and 1080p
i.e. it's really not a concern.
What is a fact is that different people have different levels of visual acuity.
Unless you can cite from something more reliable than 'Which' magazine, you don't get to call it a scientific fact.
I can CLEARLY tell the difference between 720p and 1080p at 4 feet on a 28" screen.
I've tested this enough times to know that I'm not just kidding myself.