If our info is correct, AMD has no competition for the HD 6950, more precisely - Nvidia has no card in the market segment AMD is aiming at.
According to what we have heard from the industry sources, AMD will aim its top Cayman, the HD 6970, at Nvidia's GTX 570, and according to AMD, HD 6970 should end up to be a faster card. On the other hand, the HD 6950 story is completely different as according to AMD, the HD 6950 is in a "class of its own", and simply has no competition.
The story is quite simple, there is quite a big gap between Nvidia's GTX 460 and GTX 570 and AMD is quite happy with the way that AMD HD 6800 series competes in this particular performance segment. For example, the average GTX 460 with 1GB of memory retails at around €150 to €160 in Europe while the average GTX 570 retails at around €350 (somewhere less somewhere more, depending on the region).
Bear in mind that the HD 6950 has 2GB of GDDR5 memory, and should end up significantly faster than the GTX 460. The price of both Caymans isn't carved in stone of course and is something that AMD can change quite easily. Having said that, the HD 6950 should probably end up somewhere between €250 and €300 at least according to the market placement.
In any case, we'll know for sure next week.