I know for domains that aren't at domain functional level 2012 you cannot recover from snapshots due to problems with USN rollbacks. With 2012 and newer hypervisor technologies that has been fixed.
We are looking at some different backup technologies that use VMware snapshots as part of their solution (Veeam and Unitrends to be precise). I want to make sure that I understand something correctly. Snapshots are a problem with Domain Controllers, but if the backup technology is VSS-aware, the USN rollback issues are taken care of. A more generalized statement would be: using snapshots on a DC is okay as long as the application taking the snapshot is VSS-aware. Is that a correct statement?