
after 8 weeks using this
sharp lc50ue630x uhd 4k tv, let me summarize my experience with it:
.. good video quality; 1080p, bdmv, bluray, 4k videos - excellent.
.. good upscaling for 720p, 1080i videos
.. vibrant colors.
.. the android within is good - capable of doing any 2/16gb lollipop 5.1 can do.
.. the android within can take a good no. of apps, performance is no lower than any android box.
.. works very well with netflix hd/uhd4k even on wifi.
.. works well with iflix (iflix is all sd but when upscaled, very acceptable).
.. hypptv 1080i channels like bbc earth, travel & living, natgeopeople come out sharp and bright.
.. usb playback can handle all common formats incl mkv, m2ts.
.. toslink digital output is dts/dd capable.
.. a surprisingly cool tv, does not even get warm.
not so good:
.. somehow, i find the dark scenes a little too dark, the bright scenes a bit too bright. don't know if this is a characteristic of all 4k tv's..?
.. all hmdi's video setting is restricted to a choice of std, movie, pc, dynamic or dynamic fixed. u can change the variables in each set but that will apply to all hdmi's. this is not as good as previous models where u can change the variables in each setting for every hdmi input and save as user1, user2, etc.
.. all inputs and outputs incl hdmi, usb, optical, lan are at the back of tv, not side - access difficult for wall mounted cases.
overall, i am very happy with the tv.

Overall I'm happy with the picture quality of the 630x too, I feel the only weakness is in bright areas, because the brightness level seems too low or it maybe the panel can't produce high brightness. This seems to be the characteristic of 4k panels. However the black levels are good and if the room is not too glaring, the picture quality is excellent.