My Panasonic plasma went out a few months back, so I replaced it with a 4k Sony. Best TV that I've ever seen. It makes standard HD look better. Royals games are gorgeous. Netflix produces some shows in 4k (Daredevil, House of Cards) that stream 4k if you do it through the app built into the TV. If you run it through a Roku or Apple TV, it will flip it to 1080p by default. However, you need to have the necessary internet speed to stream 4k. I have 24mb and there's some lag from time to time with 4k content.
My suggestion is to get one good 4k in a room you watch a lot of TV in, and then buy Vizio's for every other room. I'm going to hang a 48" 1080p Vizio in my bedroom soon, and that plus a soundbar will put me out about $550. I got my Sony for about 50% off as they were clearing out the previous year models, so I paid about $1400 for it.
To be 100% honest, I love my Sony, but I'm probably just going to buy Vizio from now on. Their high end stuff in the 4K range is really nice and about 50-75% less than a Sony or Samsung. I plan to hang a 60+ inch TV in my basement sometime in the next couple of years, and I'm definitely doing a Vizio.