Perhaps my experience will be instructive. Most of my sites were hit, I will give example of two sites and their fortunes. http://thailand-dealer.com went from page 1 to between page 10 and 20 and http://www.jim4x4.com went from page 1 to page 4 and further down. jim4x4.com has returned to its original ranking on page 1 but thailand-dealer.com fortunes have improved only slightly, it is between page 2 and page 10 on its searches. thailand-dealer was admittedly over-optimized and it will take some time to clean it up. jim4x4 was penalized it seems for no reason and has returned on its own to its original place. All of my sites which had over-optimized content and bad links are still suffering but all other sites are returning to their original ranking. Initial Panda and Penguin attacks were brutal and killed many good sites with medicre ones. Algo updates are restoring good sites back while mediocre and bad sites are still in trouble.