IMO after what Nvidia had said about it (and about ATI) that it would absolutely destroy the 5 series Radeons. It didn't.
It was too expensive. 5-10% faster at launch than a 5870 does not make it worth £100 more. So it was priced wrong, given that it had perfect competition. It was months late, it was hot, it used a lot of power, it made a lot of noise.
Which the 5870 did none of the above. So it lost, miserably, hence it was a complete failure in both spec terms and PR terms.
It saw the end of many companies, one of whom being BFG. There was hardly anything at all positive about Fermi's launch, other than the laugh it must have given the top bods @ ATI.
Was it only 5-10% faster?
I shall have to go and have a look around at the old reviews, I thought it was a fair bit more than that.