I installed the Netflix app last month on my UBOX4, awful experience. Menus are all over the place, and it buffer like crazy, most probably due to either the CPU not being able to cope with the video codec or not enough memory. Uninstalled it after a few hours.
I then installed the Netflix app on my PS4. Absolutely brilliant. Easy to navigate and beautifully laid out. No buffering at all even with my 6MB broadband. In the menu, scrolling over a show and it would auto preview, brilliant.
netflix on my 2014 sony bluray streaming box was pretty decent, no buffering issues, fast ui, on the other hand, youtube after the recent few updates, so slow ui, painfully slow, i don't really use netflix on my ps3/ps4 nor youtube.
on my new 55" hdr tv, excellent on both netflix and youtube, it's super awesome, HDR is such a game changer for me , significantly noticable than 4k, 5.1 dolby digital plus (at new higher bit rate now) is really decent.