The first reviews of Sony's 3D games for the PlayStation 3 are coming in from E3. Keep in mind that the games being shown are alpha or even pre-alpha, so the experiences that reviewers are having could improve by the time the games are released. Nevertheless, reviewers are complaining that the resolution of 3D games is significantly lower than that of the same games in 2D mode. In addition, the requirement to use 3D glasses both decreases contrast and makes everything look darker; this is especially a problem with adventure and first-person shooter games that already fairly dark to begin with. The combination of these two problems makes some games much less enjoyable in 3D.
The reason that the resolution of 3D games is significantly lower than the same games in 2D is that the game console has to render images twice as fast in 3D than in 2D. Even the vaunted Cell processor in the PlayStation 3 doesn't have the horsepower to double its rendering speed for complex images, so game designers have to render lower-resolution images for 3D and hope that the 3D effect compensates.
It may take a new generation of game consoles to provide 3D games that look as good as today's 2D games. Nintendo is hinting that the successor to the Wii will be built for 3D from the ground up, and Sony's likely to find that it will take a PlayStation 4 to truly do 3D justice. Dual GPUs are likely to be needed in order to render graphics equal to the best of today's 2D games for 3D.