There will be little difference if it's stereoscopic. At that point the main things would be motion and positional tracking as well as screen resolution.
actually FOV, refresh rate, latency and resolution are all deal breaking aspects regardless of it being stereoscopic or not. and that's a ridiculous "if", considering that without stereoscopy it will not be true VR and just be a personal viewer display with 3D. which is exactly what the HMZ is and this is not.
The price point will have to be very attractive if they have any hope of making it main stream. If there's one thing we can learn from Microsoft, it's that the consumer base can be very resistant to change.
if there is anything we can learn from MS is that a lot of people bought overpriced cameras called kinect. and that a lot of people also bought systems overpriced with another revision of the camera. so being optional this can actually be a bit expensive and get good sales, all it needs is to be good, aka meet expectations instead of failing them like other products.