It will really help consultants who are planning / performing the Exchange 2010 transitions in their companies or for their customers. The reports will alert you if there are any issues within your organization, which could prevent you from deploying Exchange 2010. For example, the Exchange Pre-Deployment Analyzer will notify you if you haven't deployed the minimum required Exchange service pack on all your existing Exchange servers.
This tool focuses only on overall topology readiness and not the ability to run Exchange 2010 on the local computer. The scan also performs a deep analysis of each existing Exchange 2003/2007 server to verify that it has the necessary updates and configuration in-place to support Exchange 2010.
For more details, refer the download link - ExPDA