I want both. I want Sony VR and I want the Oculus, Valve have already said they're not making VR exclusives, Sony are a better developer than any studio that would make a VR exclusive.
Ultimately, while looking around a game designed to be played with a mouse is cool, VR should be treated like a new medium, and designed like that. Sony can spend $20/30m on a VR exclusive, no one else will, so even though the experience won't be as crisp, no one else will be able to provide that kind of content, and that's what I care about personally.
As for 3 to 4 years, that assumes Sony have never told anyone about their VR unit, and considering we've been hearing about demos for more than a year, that's obviously not true.