I made a test order of one of these products for evaluating whether they are any good for mining. The 4 GB video RAM on the card and the supposed graphics chip on the card would have made a very good deal.
But it became apparent immediately that this was an outdated Fermi gerneration chip, despite the card being recognized as a GTX 660 by the driver. The card ended up on my scrap heap because it was useless for my purpose (high power consumption and low performance)
At the time I assumed it was some kind of OEM product (relabeling older chips under newer product names is very common in the GPU business). But the investigation of the c't magazine seem to indicate that there is some VBIOS tampering going on and that this is not happening with nVidia's blessing at all.
I'll be following the story closely to see what the outcome of this clusterfuck will be.