Can't want for the outcome....
AMD, who had the low power usage with nice performance, is going GTX 470/GTX 480 style.
nVidia, who had the high power usage with great performance, is (likely) going 5890 style (using 5890 cause it would be more like a 4890 than a 4870, bit more power usage than usual, but not as high as GTX 480).

Who has mastered 40nm more? We will know it in less than a month.

I must admit that I hope Cayman wins this one. Surround would require 2 cards, SLI compatible motherboard and use a lot of power (say 750 Watts for 2 GTX 580s & 3 monitors). With the AMD solution only needing 1 card, it does have a benefit when the high-end are really power hungry.