Keith Crosley, Director of Market Development at Proofpoint (www.prrofpoint.com), says:

Think SaaS to minimize costs without sacrificing security: Analysis from Osterman Research (available from Proofpoint free with registration here: http://www.proofpoint.com/id/saas-email-security-costs-whitepaper/index.php) suggests that, in nearly all cases, the Software-as-a-Service deployment model offers the lowest total cost of ownership. For a typical SMB organization, savings are typically 60 to nearly 90% over on-premises deployment models, driven by savings in labor, capital equipment, bandwidth, storage and other areas. Analysts from Gartner and Forrester frequently advise their clients that, especially for inbound (anti-spam/anti-virus, etc.) email security, there’s no reason not to deploy those functions as SaaS.

Select solutions that minimize administration overhead: In one report Gartner says that “reduced administration overhead” is the number 2 concern of email administrators. Of course, every organization will have slightly different requirements, but you want to look for solutions that have: Easy installation (“wizard” type installers that provide optimal default settings, pre-configured or easy-to-configure appliances, etc.); GUI-based administrative interface that simplifies common tasks; for appliances, active clustering and automatic configuration and policy synchronization among appliances in multi-box deployments; centralized quarantines; easy integration with directory systems like LDAP; visibility into email queues; automatic updates to anti-spam/anti-virus engines; simple software updates (e.g., “one-click” type installations with rollback options).