Left 4 Dead 2
AMD HD3D and the TriDef Ignition Driver:
Good 3D result with Virtual 3D mode
In standard 3D mode, the TriDef driver demonstrates a number of anomalies (most notably, severe water reflection artifacts). If you want to play a level that contains a significant amount of water, Virtual 3D mode saves the day with a great stereoscopic result, despite subtle depth buffer anomalies.
Nvidia 3D Vision:
Good 3D result with lowered details although water artifacts are unavoidable
3D Vision has problems with film grain, the skybox, and water reflections. Film grain can be turned off and the skybox problem can be minimized with a convergence adjustment. But water artifacts can’t be eliminated. These artifacts are very noticeable. Just how big of a problem they turn out to be depends on the scenario you're playing. Some levels have a great deal of water, but many levels have none.