Some observations include front page rankings that appear to be delisted (or "dumped way back," as one person puts it). He notes that one of his websites that has been up for over a decade is now totally gone with the exception of 2 pages that were updated in 2001.
News results also seem strange. A 2003 CNN story is occupying the #10 position in search, observes another member. Old documents are making their way to the forefront, whereas new documents are hidden.
Many people are noting multiple subdomains occupying more than one spot in the top 10.
The shuffle is definitely a big concern -- some results from the top spots are being relocated. Someone calls this "crazy swings." Sounds about right.
Matt Cutts is still looking for feedback about these changes, and he has been checking out the forum thread.
Forum discussion continues at WebmasterWorld.