There are a few nice news added that you might find useful. Revision Clouds are easier to create and modify. Using the REVCLOUD command the new Modify options makes it possible to draw new revision cloud segments as well as erase selected portions of existing revision clouds.
I will keep updating the AutoCAD 2016 page with more about this new version as well as make some blog posts about specific new or updated features.
A good thing is that the file format is still the same old DWG 2013.
Most custom programs that work for AutoCAD 2015 will also work in AutoCAD 2016. In near future all JTB World apps will be updated to fully work with AutoCAD 2016. Several apps on Autodesk Exchange Apps are already updated for AutoCAD 2016.