The experience of most users is that the GeForce line of cards provides nearly identical performance to the Quadro, at a fraction of the cost. I'm not up on the latest specs, but just looking at the amount of memory, those two cards you've listed seem to imply a much more recent/powerful GeForce and an older/weaker Quadro. It seems likely to me that you will get a LOT more bang for your buck with the GeForce.
The only downside is that the GeForce line has never been officially supported by Maya, which means on the off chance you have compatibility problems you can't count on Autodesk tech support to help you out.
There's a document somewhere on the nVidia site called 'GeForce or Quadro' or something like that, and it presents an in-depth comparison of the two technologies. When I read it, I found myself underwhelmed with the Quadros--given the substantial price difference.
Do a search of the archives here to find how others have weighed in on this issue.