I have the 65" Samsung 4k ultra hd curved 9000 series.
Don't get me wrong its an awesome TV. But I paid waaay to much for it because I fell into the trap of having to have the newest and best thing at the time. Spent over $4,500 on it. A few months later samsung had the 9500 series and now an entire line of SUHD tvs.
Also my 4k really only shows up on select netflix shows and some sporting events. However even that is restricted by my time Warner Internet. It may be a beautiful 4k picture for 10 minutes, then loses it for a few minutes as the Internet tries to keep up.
Someday down the road I plan to get my dream tv. 78 inch OLED. Light years ahead of ultra hd. LG has it on their website right now for $25,000, so obviously it will be some years until that price comes down