As seen on DPReview:
Adobe opens door to second Lightroom: Digital Photography Review
Some interesting sounding features, especially the integration with Photoshop. Shots can be selected for panoramas or HDR output in Lightroom itself.
It is now very multi-monitor aware, some of the features sound really good.
the 10,000 pixel limit has been raised to 30,000 because of the panoramas, which is good, I have some pans that it can't handle already.
Release Notes here