The major feature upgrades include:
You can now quickly scroll through the video results like you would in Bing Image search. Bing will dynamically load more videos as you scroll. They call this Infinite scroll, something they came out with back in 2009 for their image search. Google then "copied" it a little bit later.
Larger Preview Thumbnails
In the search results, when you see a video, hovering over the video with your mouse will show a larger preview than Bing has shown before. Bing said "the videos also received updated treatments, such as 16x9 images, embedded video length time stamps, and icons to help you quickly navigate the results."
More Related Content
Bing also added a row of tabs on top of your search results with related content, similar to how it is done on Bing Image search. Here is a picture of the tabs:
Larger Video Viewer and Filmstrip
Finally, the video viewer was increased the size of the video player and added a filmstrip option.
Forum discussion at WebmasterWorld.