Externally identical to the ADR2 60Si, the ADR2 120Si also records double-capacity tapes, i.e., 60 GB net. The 60/ 120 GB cartridge is substantially longer than the 30/ 60 GB tape. The drive, however, reads both types. At four hours and ten minutes at a nominal transfer rate, writing to a tape takes comparatively longer. In the group with capacities of over 50 GB, the ADR2 120Si is the slowest model.

Similar to the ADR2 60Si, there are general compatibility problems with backup programs. Use of Backup Exec is still not certified. Nor is the widespread Arcserve program supported. Yet Onstream does supply Tapeware XE 6.3 from Yosemite, thus making an additional software purchase unnecessary.

Its low price tag makes the Onstream ADR2 120Si attractive. But because of the lack of software support, Onstream has gambled away a better ranking in the test. At $1.58, the tapes' price per gigabyte is also a good value. Still more interesting in this price bracket, though, is the ExaByte VXA-2.