This is an interesting article regarding Autodesk Design Review 2013:
Here is another tip, you can also use Autodesk Navisworks Freedom 2014 or Autodesk Trueview 2014 to open/view Autodesk dwf or dxf files. Both of these Autodesk programs are free*.
*Free products are subject to the terms and conditions of the license agreement that accompanies the software.
As of April 2014, all the products have been updated to 2015.