Yes, the Image Quality of 3dfx Cards is still one of the best existing, when it comes to vivid colors
Anyway, you might increase your performance and image quality by using the latest Renderers for UT.
Those got (silently) upgraded in September the last time.
The two latest releases of both OpenGLdrv.dll and D3Ddrv.dll were specifically aimed at helping ATI Radeon and NVidia GeForce owners to redeem much of the Performance and Image Quality back.
Going together with recommended Replacements for the respective entries in the unrealtournament.ini, I know those do help
alot!...
After all, I had to get UT back working with my R9700pro as well. It's working fine, very fast OpenGL with S3TC Textures... but on the Voodoo5, it somehow looked better when it came to colors.
Nice Page with all Listed there is :
http://www.gweb.me.uk/gweb/ut.htm