We're considering StoreOnce 5660.

StoreOnce advantages include Catalyst backups, immutable backups, and ransomware protection on the Catalyst Store. Data Domain Boost can offer some protection, but not as extensive or as fast as the HPE Catalyst backup store. The performance of Catalyst backups is much faster than DD Boost. 

Additionally, the performance of HPE Catalyst backups is significantly faster than DD Boost. DD Boost can reach up to 11 terabytes per hour, whereas StoreOnce Gen4 Class Series models offer backup performance of up to 36 terabytes per hour.

There are a lot of products in the market for backup solutions. Data Domain has a lot of advantages, which is why my clients choose this solution.

We're always evaluating other options. Right now we're comparing this solution to Cohesity. We've learned, however, that Data Domain is much more scalable than Cohesity, so we are not likely to switch to them.