Hence, if you glance through, Microsoft has been upgrading the SBS versions over the period of time which also meant upgradation of the Microsoft Exchange Server. For instance, Small Business Server 2003 includes Microsoft Exchange Server 2003 which is 32-bit only and doesnt install on the various 64-bit versions of Windows Server 2003. On the other hand, Small Business Server 2008 uses Microsoft Exchange Server 2007 product, which has introduced advanced e-mail and calendar functionality to it. Exchange Server 2007 uses a 64-bit version and delivers a seamless end-user collaboration experience and unparalleled security features. Other contrasting feature of SBS 2003 Microsoft Exchange Server 2003 and SBS 2008 Microsoft Exchange Server 2007 is that the later version has built-in support for Microsofts Hyper-V virtualization platform which also means that it will be relatively easy to virtualize Exchange 2007 system down the line making it simpler to implement a disaster recovery system for email. Thus making it possible for the organizations to be in communication with its customers all the time!
Yet another interesting and glaring difference between SBS 2003 Microsoft Exchange and SBS 2008 Microsoft Exchange version is the anti-spam feature. The new version includes an anti-spam migration tool unlike the earlier version which reduce the amount of spam you get with support for content filtering and Internet IP block lists. Other improved features of Windows Small Business Server with Microsoft Exchange 2007 include improved calendaring, unified messaging, improved mobility, improved web access, 64-bit performance & scalability, command-line shell and simplified GUI, improved deployment, role separation, simplified routing, a new command-line shell and scripting language for system administration, unified messaging that lets users receive voice mail, e-mail, and faxes in their mailboxes, and lets them access their mailboxes from cell phones and other wireless devices, improved database size limit, and increase in the maximum number of storage groups and mail databases per server, to 5 each for Standard Edition (from 1 each in Exchange Server 2003 Standard), and to 50 each for Enterprise Edition (from 4 groups and 20 databases in Exchange Server 2003 Enterprise).
All in all, SBS 2008 with its renewed Microsoft Exchange Server 2007 component is definitely worth grabbing, and it is more affordable as Small Business Server hosting from a service provider. So if you are still using the older version, dont forget to switch over to the new version.