Understanding Exchange Usage: Analysis & Reporting

I'm currently working at Quest Software as Product Manager for a number of Microsoft Exchange management solutions, including this one - Quest MessageStats. MessageStats focuses heavily on Exchange usage, capacity and service delivery metrics, and includes great inventory reports to help out in pre-migration assessments (or other Exchange assessments) if you're planning an Exchange migration (from Exchange 5.5 to Exchange 2003, for example). [Quest Software is a vendor with many solutions for Windows and Exchange management & migrations.]