Its title as fastest consumer GPU in the world is completely irrelevant.
Its performance doesn't justify its cost, compare it to 2 4870s in crossfire, which, while they aren't DX11, represent far better value for money.
Even the 5850 is far better value, it costs 2/3rds the cost of the 5870 but gives about 80-85% performance of a 5870.
No-one ever buys the top performing enthusiast part for VFM

I knew the 5850 was by far the better bang for the buck but having waited since launch of my old 512MB 4870 to upgrade I wanted to treat myself to the best.