From kotaku.com:

Major Nelson even agreed to shoot this video, and while I put him to work he revealed that this is his own personal controller. The new d-pad is easy to transform and the alternate, raised-cross mode feels like it will be good for games that require precise horizontal, vertical and diagonal inputs -- you know, like fighting games.

We knew about the transforming d-pad, but did you know the analog sticks have changed? They tilt the same, but the shape of the depression on top of them has been tweaked. The old raised bits are gone and the center has a deeper depression. I'm not sure what the consequences will be of the small change, but the new stick did feel comfortable under my thumb.
Full Story: kotaku.com