I have a Vive and I've tried Oculus CV1. They are very, very, similar. 90hz, 1200x1080 per eye, low persistence OLED with global update, large fresnel lenses.

Until you get to input and mobility: Xbox gamepad vs motion controls. No contest. Yoga-mat scale standing without full rotation vs. room scale, walking around with 360 rotation: again, no contest.

Oculus wins on weight so far, though I haven't tried the Vive Pre yet.