NVIDIA has had its own 3D Vision out for 12+ years now. While those that have used it say it is great, there remains very little software available for it.
I asked a question on here about it, for any who have used it, no replies. Same in other gaming forums.
Occulous Rift has had a lot of fanfare. Hopefully it will be adopted. But unless software writiers are prepared to invest in it it, it will probably be another expesive toy lying on the shelf.