The hardware solution they offer is a set of hard drives by Rorke, set for RAID5, that would be installed at the customer’s location.
RAID5 allows for the set to lose one drive and still be recoverable.
RAID6 would allow 2 drives to go down and still be recoverable.
http://www.sonasoft.com/products/microsoft-exchange-migration/exchange-2010-migration-services/
The migrations services and their vault claim says those e mails did not just go away, and even if there is a Raid5 or Raid6, there should be emails available from somewhere. NO WAY do you lose important e mails that are told employees DO NOT DELETE due to law.