Great idea for a thread! The RealorFake4K site sounds like a great resource. I don't have a 4K set yet, but I was hoping to pick up the Unforgiven UHD release and I'm glad to see it in the "real" column!
Seriously, everyone who works in film, or imaging science, or display engineering, or who even remotely considers themselves a home theater nerd (aka thread members) need to watch the videos as it will help your understanding as to where what you watch came from and what pixel count versus real resolution is.
Also there is an American Cinematographer article about it here.
Direct download of video 1
Direct download of video 2
Warning: Around 2GB each. Watch on your best display device if you can. Doesn't need to be 4K because the cinematographer breaks it all down by zooming into details in part 2. Super impatient or ADHD? Skip straight to part 2.