I remember back those GeForce3 days, I got myself an ASUS one that included a bunch of 3D glasses. Despites the lack of support from both ASUS and nVidia, I could play Vampire : Redemption with I nice 3D effect.
At that time I had several complain like some UI element such as the HUD and the cursor would jump out to my face in a very uncomfortable way, and also the poor resolution I was forced to play at due to refresh rate needs. The real plague of it was the strain it beared on my eyes/brain, after around 20 minutes playing it would make me feel like there was a rave party in my head. So I wrongfully thought that next step would have been autostereoscopic screens such as the Philips 3DWOW, but it seems that we are back to those old fashion 3D glasses.
According to Guru3D they improved both the easy of use and the comfort, however the price range and the limited choice of compatible hardware might prevent one from adopting the system, moreover if nVidia abandon their support in a couple of years or less as they already did in the past…
To see their full review it is over here: NVIDIA GeForce 3D Vision review