I am in the process of building a new 3D Workstation for the high-end 3D art programs I use: Vue, Maya, ZBrush, Metal Ray.

Mainly, I am trying to decide between the new nVidia 680 or 690 cards for their "CUDA" cores or the AMD Radeon 7970 6GB OC special edition versions. Other software I know seems to work better with nVidia and even take advantage of the "CUDA" cores like Adobe Suite CS6. So, I am not sure which is best at this time.

It is said that the new nVidia 6.xx cards are limited in compute functions and you can see a real difference in benchmarks. Yet others will say stay with nVidia regardless because they run better with most 3D software and is what most suggest typically. Also, I have seen where AMD cards in the prior versions had issues with some features working like "Shader Billboards" for Vue according to their list of compatible cards (hasn't been updated though). Is that still true and what about the most current AMD cards and drivers?

If I could afford a high-end nVidia Quadro like the 5800 or 6000 I would get it, but I would prefer something more along the lines of a high-end gaming card like the 680 or 690 but only if it is not bad for 3D rendering. Also, I was told by some techs at Maya and e-on (Vue) a 690 card won't help over a 680 because it is like two 680 cards in SLI and most 3D software can't use duel GPU cards with added benefit. Instead, techs at e-on and other places say to look for the best single GPU card you can get with the fastest clock speed and memory. Sort of like the GTX 580 "special edition" models that had factory overclocked speeds and more memory.

Any advice here on what current video cards you know work best for a 3D Workstation with no issues and good results would help.