There is no evidence to support that ATI's aniso method is fundamentally of higher performance.
Erhm...I presume then that there is also no evidence to support that ATI's aniso is "fundamentally" of lower quality.
You're just fogging the issue. Sure...with high enough transistor budget (additional logic) and bandidth, etc, you may 'negate' a performance penalty.
Though one can do the same for increasing aniso quality on the Radeon. All that matters is practically speaking
how do the two compare?
GeForce=More uniform quality
Radeon = faster.
Quite simply, the GeForce4 does not have the ability to calculate the degree of anisotropic for two textures per clock...
Doesn't the GeForce3 have that ability though?