Overall it does save a few seconds here and there.

However it might hurt your eyes a little with the constant transitioning. Like for example, when you start typing, immediately it shifts the search field to the top, so you can't track your typing for that brief moment.

If you have a slower connection, it probably doesn't change much from a usability perspective.

I also like the fact that now the different pages of the search results are AJAXed in rather than loading an entirely new page.

google is full of champions! They deserve an award, or at least a pizza

Google's Doodle team brightens my mornings.  

google's the shit!