Phew...reading all these initial posts without many using this device had me plenty scared. I thought I'd be taking this thing back in a day or two.....Not happening! It's great! I am watching on a 2016 LG 65E6 OLED that was professionally calibrated for SD, 3D and HDR. As mentioned earlier these sets do not allow for Dolby Vision calibration. The Apple TV immediately asked if I wanted to try HDR and I clicked yes, setting the box to 4k HDR 60hz. I could immediately tell the color was off, but since that input never used HDR I had to choose my HDR user settings. Immediately the UI came to look as it always did. Not blown out at all. The last few nights I have been watching bits of Creed. Obviously in 1080P. It is listed in iTunes as Dolby Vision. I could immediately see the color pop the way it hadn't before. Switching to Mad Max:Fury Road colors matched the 4k Blu-ray. It does seem that movies in Dolby Vision are being out put at the HDR mode your set is capable of. On to HDTV (1080/720P). Directv Now looks very good. I mainly watched some hockey, MLB Network and HGTV as these are usually my best looking channels. Remember the set was calibrated for HDR so standard def is very close. If anything there may be a little more pop to the picture that is almost more realistic. If I have one nibble is that sometimes the up conversion to 4k may ever so slightly smear fine objects with fast movement. You almost have to look for it though. Pluses and minuses Pluses Great 4k PQ Screen Savers are THAT much better in 4k HDR Movies with Dolby Vision will play in the mode your set is capable of. Lightning fast. Apps loaded up in what felt like seconds. Overall better PQ than ATV 4 which was pretty great. Minuses As discussed ATV does not switch refresh rates on the fly. Some very minor smearing up converting 1080/720P Blacks are a little crushed viewing 1080\720P in HDR mode Professional TV calibration is highly recommended. I'm really struggling to find issues..Relieved and delighted.