how would ua6800x 50" compare with sony x7500F 49" and samsung NU7400 50" in terms of picture quality?

i intend to use the tv in my bedroom (dark lightnings) for:

1) HK drama streaming
2) Football
3) movies
4) Netflix 4k

Not sure whether to pay the extra for samsung nu7400" and get an android box (Mibox international/minix neo u9-h) or settle with either sony/sharp.