You are going to see lots and lots and lots and lots of blog posts about Revit 2013 very soon …

EDIT – Official Autodesk link – http://images.autodesk.com/adsk/files/revit_2013_comparison_matrix.pdf

Here is one that should provide you with a quick overview of the new features:
http://www.cadac.com/nl/brochures/Documents/autodesk-revit-mep-2013-comparison-matrix-en.pdf

Note – you can find this document by typing revit 2013 release comparison_matrix_en.pdf into a Google search …