I've recently used both and think they're equal in terms of immersion when the Vive is roughly around the minimum space requirements. For gaming, I could take either; for non-gaming experiences, I haven't seen anything on the Vive that wouldn't feel similar on the Oculus or vice-versa.

If you have a large open space the Vive may pull ahead, but I haven't tried anything that could take advantage of that.

FWIW, I was sold on VR when I first tried DK1, but now having tried the consumer version and the Vive (years later), I'm even more excited.