It's awesome and I think it's a far better solution then a dedicated virtual cabinet.
I was surprised about the comments made of how this type of a setup could replace real pinball machines and impact prices. I think that's a bunch of BS. Even though this setup is cool it's still a simulation, you have to strap a headset to your face and the social aspect of the game is gone.
While the creator thinks this could replace real pinball I think it will do the opposite and result in more people buying real pins. There's a bunch of racing simulators out there, several that work in VR, yet it won't stop people from wanting real Mustangs, Cameron, etc.
I have a Rift on preorder and definitely plan to build something like this.