The cards will not be available for purchase until March 19th, but the reviews are out right now! The HD 7870 and HD 7850 are powered by the Pitcairn GPU and the will be priced at around $350 and $250 respectively. When you compare the HD 7870 to the HD 7700 you may notice that the HD 7870 has twice the stream processors, texture units and ROPs. Looks like AMD was able to squeeze the contents of two Cape Verdre GPUs (1.5 billion transistors) onto one 2.8 billion transistor GPU.
The $300 to $399 price range is where the HD 6970 and the GTX 570 live right now. Looking at the reviews, the HD 7870 is faster than both of those cards. Since the HD 6970 was the fastest card in the $300 to $399 category, I have updated the Superlative page to crown the HD 7870 the new winner in that prie range.
Here is the Asus HD7870-DC2T-2GD5 for your eye-joyment: