The largest difference is that they removed the “more by” link that linked to additional stories written by that author. The other changes include that now clicking on the author’s image and name will take you to a similar result set that you would have seen if you clicked on the old “more by” author link. I believe the author image and name use to take you to that author’s Google+ page, when available. Now, the only way to get to the Google+ page of the author is to click on the number of people who have circled that author.
Here are before and after shows, starting with the new interface, followed by the old.