I have the AIW radeon. In short, it rocks, and I'd pick one over a GF2 any day.The principle architecture difference between the GF2 and Radeon is that the GF2 has four pixel pipelines with two texture lookup units per pipeline, whereas the Radeon has two pixel pipelines with three texture lookups per pipeline. Now, using bilinear filtering and only two textures, the GF2 will be speedier than the radeon per clock cycle (although not 2x, the benefit of each additional pixel pipeline is less than the benefit of adding the one before it due to memory bottlenecking) however, that third texture lookup will mean that you can achieve some extra effects on the radeon with comparatively little slowdown.
Trilinear filtering, for example, needs the value of a texture from 2 seperate MIP-maps of the texture to determine the pixels eventual colour.. Which is fine, if you happen to have a texture unit spare as you do on the radeon (assuming one lookup is being used for lightmaps), but without the extre texture lookup trilinear filtering slaughters the framerate on the GF2..
There are other benefits of radeons, such as support for all the current methods of bump mapping, the ability to do compressed textures (the GF2s S3TC implementation is a little fuX0red).. Anisotropic filtering is nice and doesn't really cost a great deal of performance.. then there's the hyperz technologies... priority buffers.. vertex shaders (there's some little bugs in this, i'm not sure whether they're silicon or driver problems though)..
On the down side the quality of 16 bit on the radeon isn't great.. sometimes even looking a bit like parchment if a lot of multitexturing/alpha blending is going on.. but 32bit is free from those probs..
New drivers seem to be being released every two to three weeks..
I'm sure there's still stuff I havn't mentioned.. but a radeon is my recommendation..
