Comparable to a Barracuda email appliance, these units retain email that is quarantined as well as provide cloud layer to support it. It is best suited for a medium size company as the devices are often not as scalable as Barracuda.
Filtering system is very strong, more often than not blocks bad email.
Does fine job filtering and configuring content filtering for extension types such as ZIP or RAR.
Intermediary between Internet and email system provides extra layer of security including ability to spool email in the event of an email system outage.
Outbound encryption feature is very useful for security purposes.
The end-of-life of appliances is unfortunate as it forces a purchase of a replacement unit. Barracuda devices have a 4-year refresh cycle so purchasing additional hardware is rarely necessary.
McAfee seems to be phasing out the service over time.