The effect of 3D Shutter Glasses (and those 3D LCD screens) is limited. They are based on stereopsis... two seperate images that when viewed with both eyes things look 3D. But the image is still really 2D... if you cover one eye, you wont see the effect. This means that your brain is confused... each eye individually sees a 2D image, but your visual cortex is putting the two images together and interpretting it as a 3D image. Since your brain doesn't know for sure if the image is 2D or 3D you can end up feeling sick or get a massive headache. To add to the confusing the shutter glasses leak light meant for the opposite eye, so you can see a double image "ghosting" effect. It is also hard to focus on the 3D image on your monitor, since the frame of the monitor and your desk around it is at a different focal depth. Its like trying to keep your focus on one of those Magic Eye pictures.
If you keep the effect (the 3D depth is adjustable in the drivers) turned to max, things do appear to fly at you, but its very difficult to keep your eyes focused on it, you end up with aching eyes, temporary short-sightedness and possibly vomitting.
If you keep the effect turned down real low then the glasses are easier to use, but you still get some ghosting and the 3D effect is much less.
Since each frame is rendered twice, using the glasses will half your fillrate (big performance impact). They also half the refresh rate of your monitor, so 120 hz looks like 60hz which results in even more eye-strain.
LCD shutter glasses are a novelty... they work better than most other 3D glasses, but they still don't work good enough.