x x x there's not a lot of 4k media yet.
I have had qualms whether to buy a 4k TV, exactly the same concern as yours about the lack of 4k video sources. Then I took the plunge in Q4 of 2015.
So far I don't think about it as much as I used to. Why? Because all my bluray discs look fantastic when upscaled to 4k. A perfect example of this bluray disc is the remastered version of the movie GLADIATOR (2000) which was reissued in 2010. It is only 1080p, alright. But when Hollywood gets something like this properly made, the upscaling with a 4k panel truly stands out.
I also observe that my 1080p MKV videos with
excellent encoding bitrates (these are the big file sizes ranging from 15GB to 25GB, not the 1GB-2GB ones that suffer from artifacts because of high video compression) look great, too.
The other thing about 4k videos: they gobble up too much HD space.
So go ahead. Take the 4k plunge!