4K TV's are where HDTVs were in like, 2003. Not worth it, unless you have money to blow. By the time 4K is standard, and everyone is providing content and physical media, the TV's will blow current 4K TVs away and make them seem like ancient tech.
Unless PS4k is a real thing. Then I think there will be a push for 4k in the near future by Sony (which will be big). To the OP I say wait to buy anything though. Christmas during Black Friday or Cyber Monday is going to be the best deals, and by then I think we'll have a pretty defined sense of what (and if ) the PS4k is.