I saw to sony TVs side by side at Costco. The 4k was priced at $3500 the HD was priced at $1500. The picture was pretty on both, but the HD looked better then the 4k. I told the rep, and they noticed it as well. Both systems were on DTV. But $2000 extra, for the same if not slightly worse picture? This was at 7 feet, on 60" screens.
Before someone chews my head off, I can guarantee it needed calibrated, but the fact that the picture and color schemes just did not look that good on it's own, turned me off from buying one, or caring about it, until one of my TVs go out. I think I got quite a few years of life left in them.