idera - why it restores databases faster
From Idera's website, it appears SQL Safe inserts a "shim" (a piece of code, be it CLR or native code) into SQL Server to support what they refer to as "Instant Restore":


  Instant Restore
  
  Patented Instant Restore technology brings your database online immediately—virtually eliminating application downtime. This can save you huge amounts of time when getting back online in a disaster or searching old backups for a piece of lost data. Once online, your database acts as a fully functional database, supporting all read and write operations. SQL Safe streams data from the backup file “on demand” to support applications and user requests while completing the restore operation in the background.


This indicates, to me, that the database is not actually fully restored prior to the database becoming accessible to client queries.

I'd be just a little concerned about this style of recovery for production since anything that has the possibility of reducing ACID compliance is a risk.  Using this restore capability for development or support seems like a great idea since you no longer need to wait for recovery to complete.