Actually, the GeForce based boards are much better at 3D image quality then the G400. In terms of 3D visualization, you are looking at either nVidia or one of the more serious(although often not as good) pro boards such as one from 3DLabs, E&S or Dimaond(the "Fire GL" series, not their consumer crap).
Big difference between 2D desktops and games and the 3D visualization market, out of the consumer boards it is nVidia and then a very large gap between the rest, the rest being nearly unacceptable for the tasks(ATi is OK, along with Matrox when it will run(very buggy OpenGL drivers, 3dfx is useless).
Edit-
If all you will be using is Bryce, then I wouldn't worry too much about it. The GeForce boards should be significantly faster, but Bryce was designed to work with consumer cards and does work well on Matrox(though still flaky with the last driver revision I used it with, about six months ago) and ATi boards, though better on nVidia and I still wouldn't reccomend any 3dfx part.