Raven's Rick Johnson updated his .plan with some additional notes on the just released Soldier of Fortune demo. Here's the scoop:

Quick Note about Drivers:
If you play SoF on 3dfx hardware, you may experience a few driver bugs. On the DX7 Beta drivers, when the screen flashes to indicate you are hit, you may get random colors. Other cards / drivers may experience complete texturing problems (though SoF should disable those features in Gl which cause these problems). NOTE that these bugs are within the 3dfx GL drivers themselves, and are NOT SoF bugs! 3dfx is aware of these bugs, but I'm not sure when they will be able to address them.

Should you need more information on what the demo offers before taking the plunge to download it, then Redwood's Soldier of Fortune Demo Review may prove useful.