Tessellation performance is better than 5850 or 5870.
And it consumes less power than a GTX 460
No wonder Nvidia is lowering their prices on the GTX 470 and GTX 460. The 6870 beats the pants off of the 460 in normal performance, and ties it in Tessellation performance.
So, the 6870 falls squarely between the HD 5850 and 5870 EXCEPT for tessellation performance, where the 6870 runs away with the win.
This is getting juicy. I can't wait to see the 69xx cards!