I did have a look at the 8K, not quite comparing apples-to-apples since one is textured and one is not, but I would say the 8K was sharper. That said, there wasn't anything in the 4K that looked bad in any way.
I like these images just because we don't see too many VR images yet, plus I like the scale of the place, great to see such a huge space done in VR. Then the sunlight was also really good, I take it that was volumetrics? Never thought on trying those in VR, will have to give it a go sometime just for the fun of it! It looked awesome in this scene, however it was created :)