DP 1.3 needs to hurry up and become mainstream so we can get some 4K@120 love. Supposedly, HDMI 2.0 might be able to pull it off to some extent.
I picked up a cheap Seiki 39" 4K TV from Newegg about 6 months ago (less than $500) It actually has been a pretty fantastic TV. I don't have TV service, I just use a small, but very powerful workstation as a media center PC. I cut the cord on TV over two years ago and haven't looked back. I typically run at 1920x1080@120, but occasionally flip it to 4K for the minimal content I can find. Last I checked, Netflix wouldn't do 4K on a workstation which was disappointing.