I know AMD's cards, at the moment are a better value, but that doesn't matter for me and here is why: I cannot erase from my mind the negative connotation that the name "AMD" has. For me, AMD has tainted ATI gpu's forever with their abysmal CPU performance and the fact that they have gone great lengths to make their brand name synonymous with "mid range" "low performance" "low power consumption & cost" etc. It is a psychological thing for me and I admit that, but I also can't change it. AMD does not equal high end or high performance, so I don't buy their stuff.
Combine this with my brand loyalty to Nvidia and satisfaction with their products, and the fact that AMD is a sinking ship that I want no seat on, and you have a recipe for a customer that AMD can't win over. Call me a troll or whatever you want, but I am not alone here and these are the reasons that AMD is tanking and people don't buy their stuff anymore.