Ok watched "Arrival" in 4K on Vudu. The cost was 7.99 for 24 hr rental. I had some problems getting the 4K version but it was due to the fact I had my Roku4 set up for UHD 10 bit. Vudu sent an error saying my device wasn't 2.2 compliant. I changed my Roku setting to UHD. After changing the setting I was able to view the 4K content. Vudu requires that you can connect at 11mb to view UHD. My connection speed is around 50mb so there was no problem with the download. My setup includes a Samsung 65in UHD HDR TV, Onyko receiver and 5.2 speaker configuration capable of receiving atmos audio which was active with my Arrival rental. The picture quality was very good but some scenes seemed a little dark. Would of thought the HDR format would have made these scenes lighter but I don't know for sure because I had nothing to compare it to. The movie ran flawlessly with no pixelation. The sound was awesome. It sounded like the F-16's and helicopter were flying right above me and through my house. The Atmos audio made this movie come alive. Overall I would say I got my moneys worth and will definitely rent again. Vudu had about 50 recently (2015 and after) films in UHD available for rent or purchase.