GPU for Cyces: Quadro 2000 or Geforce GTX 680

I’m thinking of building a computer optimized for rendering with programs like Blender Cycles and LuxRender. Which type of GPU would serve me best: a mid-range workstation card or a high-end gaming card? I’ve heard that the Quadro is usually the way to go with CAD-related programs, but people usually recommend the Quadro 4000, which is well out of my price range.

Should I go with the Quadro 2000 or the GTX 680 for GPU rendering with Blender? They’re both similarly priced.

Quadro:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814133382

GTX:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814130768