• Enhanced Auditing – New Exchange auditing events and audit log repository enable Exchange administrators to more easily audit the activities occurring on their Exchange servers. It allows the right balance of granularity, performance, and easy access to audited events via a dedicated audit log repository. This simplifies the auditing process and makes review of audited events easier by segregating audited events in a dedicated location.
• Exchange Volume Snapshot Backup Functionality – A new backup plug-in has been added to the product that will enable customers to create Exchange backups when a backup is invoked through the Windows Server 2008 Backup tool. Exchange Server 2007 didn’t have this capability on Windows Server 2008 and additional solutions were required to perform this task.
• Dynamic Active Directory Schema Update and Validation – The dynamic AD schema update and validation feature allows for future schema updates to be dynamic deployed, as well as proactively preventing conflicts whenever a new property is added to the AD schema. Once this capability is deployed it will enable easier management of future schema updates and will prevent support issues when adding properties that don’t exist in the AD schema.
• Public Folder Quota Management- SP2 enables a consistent way to manage quotas by improving the current PowerShell cmdlets to perform quota management tasks.
• Centralized Organizational Settings- SP2 introduces new PowerShell option that enable centralized management of many of the Exchange organization settings.
• Named Properties cmdlets – SP2 enables Exchange administrators to monitor their named property usage per database.
• New User Interface for Managing Diagnostic Logging- SP2 enables Exchange administrators to easily configure and manage diagnostic logging from within the Exchange Management Console.

As with any major service pack or update, please be sure to test all critical functionality after updating.  There have been rumors that Exchange 2007 SP2 may adversely affect BlackBerry Enterprise Server integration (as had happened in the past with Exchange 2003 SP2) but these rumors have all been speculative.