Now started to Watch Elephant tonight, the 4k Video is absolutely sensational.
Are you getting full quality? I've been putting off watching content as they're not streaming Atmos audio at the minute.
I watched the Simpsons short 'Playdate With Destiny' the other day, it had was in 4K with Dolby Vision - really impressed with the picture quality for an animation, didn't check whether I was getting Atmos or not. The nature documentaries will be far more challenging to encode though.
I hadn't had a proper look round the available content before, was impressed how much was in 4K HDR.