The stereoscopic 3D works extremely well for me, and the framerate is nearly untouched when it is enabled, which is awesome because some games take a huge framerate hit when 3D is enabled. However I do have two concerns about the 3D in Crysis 2:
1) Bloom is awful in 3D, yes, it's even worse than the over-exaggerated 2D bloom. Any object in 3D that has bloom produces this weird triple imagery effect. I have noticed that other games with 3D support and bloom tend to suffer from this as well (i.e. Mass Effect 2). Are there any plans to fix this before shipping retail?
If not... give us advanced graphics options! We need to be able to turn bloom off! (I'm sure you're tired of hearing that haha)
2) The crosshair in 3D seems to suffer from the same issue. The rest of the HUD layers perfectly, but the crosshair also has that weird triple imagery appearance. The correct crosshair is layered in the center, but to the left and right of it, there are slightly transparent copies of the crosshair, which is extremely frustrating and gets in my line of sight.
Again, if there are no plans to fix this before retail, allow us to turn off crosshairs and use nVidia's built-in 3D crosshair system

Other than that, kudos for a great 3D implementation, you guys have built the game and UI to work in 3D very well, it's implemented MUCH better than many of the games I have played.
If you can get these two issues fixed, I'd say it's up there to be better than Bad Company 2's 3D implementation.