I have a Vive and Oculus CV1.Even with all the problems with the Vive i prefer it to my CV1 in ED.Picture is brighter,the frame rate is silky smooth and the cockpit looks better for some reason.The CV1 is clearer but frame rate suffers. If i had to pick one HMD for overall use it would be the Vive. i7 5930 12GB Ram 980Ti .
I've had the opposite experience; framerate is smoother on my Oculus than on my buddy's Vive (Testing against the same computer). That being said, the difference was negligible; I'd happily play on either. Regarding clarity, it's interesting; I don't notice much of a difference between my Oculus an my buddy's Vive, but my buddy says the Oculus is WAY clearer. I think it's because I wear glasses actually; I don't look around with my eyes and use the periphery as much as he does so I am less affected by the clarity falloff at the edges of the lenses on the Vive. He still is waiting for some more fixes so he can "read the text." (I had no problems reading any of the screens in his Vive.)
In any case, Elite Dangerous is awesome in VR, no matter what VR you have! Easily, EASILY the best VR game available so far, and likely will keep that honor for a while. We are lucky to have such a complete experience so early in VR's launch!