I think they are different types of storage for different purposes
If you are looking for a storage where to put backups data you can think Data Domain is the perfect choice because it is its main use (most or all the backup softwares have plugins in ordere to manage data…
I think the most important aspect when evaluating a backup software it's starting from the needs. What are the architectures, the applications, the servers, the databases to restore ( not backup )? And also, what are the peoples that will be responsible of the backup service…