Seems that Oculus/Facebook have gotten the jump on HTC here. Without knowing what the marvellous discovery is that held back the Vive, and without knowing the target pricing, a lot of early adopters will jump on the Oculus pre-order. Hopefully we'll get a mad scramble over the next couple of days where both companies release more information.
For me, the decision whether I go for the Oculus will be its release-day pricing. If it's at or below the £300 mark, I'll be sorely tempted. But above that it goes from something I might buy on a whim even though it doesn't get much use to something that would be a more considered purchase. The pre-order carrot of EVE: Valkyrie doesn't do much for me, so the real carrot is going to be the price, especially if the Vive is to be expensive as has been rumoured.