Invested in a 4K set the other day. There isn't a great deal of content available for these screens yet; my purchase was largely driven by the PC I bought before Christmas. Oddly enough, it's mostly streaming services such as Netflix, Amazon and YouTube that really offer it. Where it's available though, wow. Exterior scenes just pop; Sense8 on Netflix is a superb example of 4K, what with the globe-hopping and all.
Anyone else taken a look at 4K yet?