Comparison: GoPro Fusion and Yi 360 VR at Max Resolution
This is not a perfect test, as the videos were shot on different days, but at a similar time of day, and the place is the same. Both videos were shot at the maximum resolution (5.7K, 5.6K) of the camera and produced to retain as much as possible the original quality using the software supplied by each company for stitching.
Yi 360 VR:
You can view at maximum quality by selecting 5K with the gear.