Creator in Autodesk shows some interesting tools and improvements about modelling MAYA 2012. He demonstrates all this features by modelling character from game Human revolution. This character is modelled in MAYA 2011, but in some videos shows add-ons of MAYA 2012.
Original article: Maya 2012
This Service Pack fix issues with stability and for example performance issues with Freeze brush and issue when Eyedropper tool picks wrong colour to some areas and many others.