Curved is a gimmick, and dying out quickly. Be sure you get an HDR equipped set. I think that will have a bigger impact on picture quality going forward than 4k, especially on screens smaller than ~60".
https://arstechnica.com/gadgets/2016...-get-a-new-tv/
If you can afford OLED, go that route. If not, find the best price on a 4k HDR you can and be happy.