I have tried via the HD6950 connected to my Samsung 3D LED TV via 1.4a HDMI cable. The James Cameron Avatar game have 3D feature. Just enable it in Game Setting and it plays. I have tried it only for a short time to show my friends but the objects really jumps out of the window.
There is WOW factor but I just don't know how it is over long time play.
As for movies, I still do not have a full length 3D movie to try. So far I just settle with the TV's 2D to 3D conversion which adds depth but no jumping out of the screen.
I've tried it on AMD cards and Nvidia cards, as well as seen a movie on it. Here is a bit of a run down on my opinion.
The AMD solution works, but only at 720p for gaming.
The Nvidia solution is really good for gaming in my opinion. It works at 1080p if you have the right setup and it really does bring games to life. It really looks like true 3D.
In movies, which I did not hook up through my cards, but directly to my monitor using my PS3, it worked (seems to be the only use I have for my PS3, is for blue ray and blue ray 3d). However, in movies, it doesn't look like true 3D like it does for games. The reason is that in movies, they still shoot the film with 2D cameras, which cause things close or far to be out of focus. Where ever the camera isn't focused on is out of focus. They then edit the film to create planes, so it appears things further away are on a different plane and things close are on another, but if you focus on those items, they are still fuzzy.
I personally am enjoying 3D vision a lot. I'm still not sold on 3D movies.
I've only been using it for a bit over a week now, so my opinion could change in time.
Let me describe how 3D is achieved, which will likely answer your question better. 3D is achieved by creating binocular vision effects by sending two different images to your right and left eyes. When you look at something at a distance, your eyes are further apart and when you look at something close, your eyes come closer together, until you attempt to look at your nose and you become cross-eyed. 3D gaming does just this. Since games already use distances to determine the size an object is drawn, it now places two objects on the screen so that each eye only sees one, and they are apart of closer together based on the distance they should be. This creates the perception of depth. Most the time, the HUD has no effect applied to it, so it appears to be the distance that your monitor is. Then things at a distance appear to be inside the monitor, and occasionally, things come at you and appear to be in front of the monitor (this happens a lot with Lara Croft, and forced me to make some adjustments with the 3D settings to prevent me from going cross-eyed).
The great part of the 3D gaming setup is that you can look at any item on the screen, and it appears to be at the distance it is and you can focus on anything. Due to your binocular vision, anything not at that depth goes out of focus naturally.