I saw it

6 GB is enough at the moment.
But I do not want to discuss, which card is faster. Over all games with both fully overclocked to a speed, where nearly all serial production models of both cards are able to reach and with 1680x1050 and even 1920x1080, both cards are fighting closely. So it is not faster than mine or mine is not faster than yours.
But I have a card which bust your card at higher res. As I will run CloD on triple 27" monitors soon, the ati is my shot.
And missing BIOS entries for new pci-e speed, the lag of gpgpu units and the memory, which is to low for high end and for CloD causes me to buy the ati. For that price, they are currently just getting some new customers not aware of the current market. Your buy is nott wrong, but with such a price and officially stated lack of some normal features (this card is shrinked in its features) is just to show a good alternative to the ati card, until they will introduce the big kepler.
So, u nearly buy 3/4 of a graphics card for the money of 1 1/4 of a same performing alternative. I personally do not want to do that.