Maybe this is of no use to you, but I found that my Voodoo 3 3000 (although on G-Rex and CGFX4) is significantly - noticabley - faster even at drawing 2D desktop items than my CyberVision PPC.
Things like tiling the backdrops of windows happens in a snap and I can't see them being "painted" any more. So far I am very pleased with my Voodoo system.

I'm not sure if a similar sort of performance is gained with a Mediator though, but PCI sure has been a great upgrade for me.
Amigaz sold me his Terratec 512i which is excellent under my G-Rex; MP3s, modules, and HivelyTracker sound fantastic on it. Thanks again, btw, Amigaz! :-D The digital out is useful too. I'm sure you can use this sound card under the Mediator aswell.
I am also using a PCI ethernet card which is noticably faster than my XSurf was. The only Zorro card I am using now is my Algor Pro.