That video appears to show that Oracle has better ride height control. When they're foiling (both boats) in that video, they are foiling but still very close to the water. I would think this has some aero advantages. I think ETNZ has just been more on the front page about technology and performance so we naturally start to see them as the ones to beat. I'm not sure we will have this figured out until, at earliest, the first race between the defender and the final challenger.