Well, 9 years in and our LNT5571F is still working like a champ. Great picture quality, no issues.
It's been a great TV but it's time for a change. I have the itch for a UHD HDR TV, so we just bought a Sony XBR75X940D. It'll be delivered later this week. I don't know what I'll do with the 71F, don't expect that it's worth much these days. I'll probably put it in one of the guest bedrooms and let it enjoy some peace and quiet in its old age.