The first thing you will notice is the new look. The new design is very basic, but allows for an "adaptive design," so that it works on all devices. Yes, tablet, phone or PC - the design will adapt. It doesn't seem fully "responsive" but it does seem to work nicely.
You will also notice a lot of trending sections. Bing will use signals from Facebook, Twitter and Bing, yes, their own signals, to bring trending news to you faster. You can see this under the "Trending Topics" section, in the carousel.
Also, you will notice a section devoted to Trending News on Facebook, which is based on news content that was "liked" on Facebook.
Bing also expanded their people and places to show you people and places based on news trends.
Forum discussion at WebmasterWorld.