-The results seem to come faster – almost 2x as fast as in the current Google search, although since there are no ads on the test version, it’s hardly a fair comparison
-There seem to be less images included in the new results
-More reliance on keyword “strings” rather than stand alone keywords
-More focus on off-page optimization elements

Here is “Caffeine” (top) and the current Google results page (bottom).

Here’s an interesting article with a bit more information.