If Nvidia doesn't make a big Kepler then this round is shaping up to be much like the last where Nvidia leads by 10-15 pct on the flagship. The difference is that unlike Thermi, now they have a very efficient chip much like Amd.
What I am still left guessing is how they achieved such great efficiency, something must have had give. My guess is that GK104 will be inferior in GPGPU computation than Fermi and will lose a lot of its features that are oriented towards the professional segment and stream computing. This chip will probably be geared only for gaming which is likely how they managed to save so much die space and still make a powerful chip.