The guys over at destructoid.com have come up with this comparison image of the old prototype remote in comparison with the final build design.
Most notible difference has to be the thickness or bulk of the remote, mainly down to the new hardware that has been added to the latest build (like a speaker, dongle-grabbers etc).

Most notible difference has to be the thickness or bulk of the remote, mainly down to the new hardware that has been added to the latest build (like a speaker, dongle-grabbers etc).