Again, this is a post processing technique, it does not add any color information to the scene, just depth info, and a shader that does a sort of conditional blur with the pixel color & the surrounding z information.
In real games like the MMO AoC, this FXAA makes the game ultra blurry compared to the hardware FSAA methods.
This FXAA is only good for games that does not support hardware FSAA, or with performance problems.
If you want max IQ & sharpness, SSAA is the best & compatible with all the rendering techniques. But ofc, the slowest.
More information here: http://research.nvidia.com/publicati...n-antialiasing