SnapMirror to tape ...
SnapMirror to tape is only useful for migrating an initial replica. If you use it to make backups (which NetApp explicitly don't support), you can only make a full backup of the entire volume, including all historical snapshots, and you don't even get a decent catalogue.
NetApp's D2D2T approach is still missing two major pieces of the puzzle:
* The ability to send snapvault deltas to tape
* A decent catalogue integrated into Protection Manager.
At which point, they will eat IBM and Symantec's ILM lunch.