Marshall - 5:00 pm on Apr 26, 2012 (gmt 0)
I think the underlying frustration here, especially for me, is when you do everything "by the book" (no black hat anything) and your site bounces up and down in Google's SERPS for no apparent reason. Whereas in BING the site remains steady. One e-commerce site I manage comes to mind. It is well established (12 years old) and in BING it has been in the top 5 SERPS seemingly forever, whereas in Google it has jumped from page one to page 30 and anywhere in between without changing a thing on the site. There is no logical explanation for it. Subsequently, one day your sales are up, the next they are down, and you have no clue how to adjust to make Google happy.
And this is way I said earlier I think Google is just trying to get people to buy AdWords.