Results: Maya 2013
When it comes to gaming-oriented graphics cards, Nvidia's GeForce dominates the Radeon. The opposite is true when we isolate the workstation products, though. AMD's FirePro beats the more expensive Quadro K5000 again, and the FirePro W5000 leaves Nvidia's Quadro K2000 in the dust. Of course, none of the other professional boards can touch Nvidia's Quadro K6000, though at $5000, it's as expensive as it is rare.
In theory, you could probably get by with a GeForce or Radeon card in Maya 2013, so long as the potential for lower color depth doesn't bother you. If you're willing to sacrifice SSAO and MSAA, there's also the option of falling back to an older workstation-class card (unless you're working with extremely large models).