This isn't so much a tip as it is a lookout for those considering migrating to Exchange 2007. First off, I really like Exchange 2007 and, as soon as Microsoft replaces some removed functionality, I'll probably make the switch at work. The new Outlook Web Access alone, with its ability to allow users direct access to their network-based work, makes this possible in my organization, as does really inexpensive academic pricing.
But, let me go back to the "as soon as Microsoft replaces some removed functionality" comment. In a previous article, I explained some of the formal reasons that organizations might wait to deploy Exchange 2007. Now, as I work more with the product, I find more I like and more that... doesn't hold up. First, at the same time that Microsoft added great new features to Outlook Web Access, they removed key components, such as the ability to view public folders through the web tool. Now, I don't know how your organizations work, but we, for now, use Public Folders pretty heavily, and have a lot of OWA-based users as well as users that work from home using OWA (I'm the CIO at Westminster College, a small private liberal arts college in Fulton, Missouri). Over time, I'm planning to migrate users to something other than public folders--probably SharePoint--but this won't happen for a while. To be fair, there has been a statement that this functionality is to return to the product in SP1, but I can't fathom why it was removed in the first place.
Second, the GUI-based management console is not a complete work. It's lacking some really important functionality. For example, the existing GUI provides no means to manage the POP3 and IMAP services that are used in Exchange. I can personally attest to the fact that many colleges and universities make heavy use of these services. Further, one of the reasons that some organizations deploy Exchange over, say, SendMail is to avoid the command line.
That said, Exchange 2007 does include a powerful, and really good, command line-based management shell from which you can perform 100% of Exchange's management tasks. (By the way, GUI management for some missing tools is slated to return with SP1 as well.)
Ok--that's enough for now. As I said, there is a whole lot to love about Exchange 2007. The reason I wrote this tip is to encourage others to take the time to severely test Exchange 2007 in a lab environment and figure out the shortcomings. Upgrading Exchange 2000 to 2003 was a no-brainer... this one is going to take more planning, folks!