as far as the fx 5900 and Pro-E goes it runs very nice. redraws just as fast as my quadro did but some things like mechanism design must use specific quardro stuff because my mechanism redraws like gears and cam surfaces are slower than the quadro.
most importantly normal zooming panning, etc and regeneration are very fast. at least as fast as my quadro was. stability seem good also even in the animation module that my 9800 pro crashed constantly in.
the 9800 pro was definately faster in all the games i play and i does noticably look better, but the fx 5900 is a nice card. don't bother spending the extra money on an ultra the 128mb is plenty fast and newegg has them starting at $330.
only bummer is that my swiftech gpu block doesn't fit on the fx, darn core is so big they has to change the mounting screw placement....