Autodesk has released a survey asking about your AutoCAD drawing comparison needs. Take about 5 to 10 minutes to fill out this survey. Once completed your name will be dropped into a proverbial "hat". A winner will be selected in about 5 days time.
http://www.surveygizmo.com/s3/513364/Drawing-Compare
Try it out. it only takes about 5 minutes and you could win $30 (USD.) Plus your answers will be used to help influence Autodesk!