Data backup solutions can be created with relatively little work using all four products. StorCase offers removable drive bay solutions for 2.5" and 3.5". The USB models we tested allow hot drive swapping, and include useful software solutions. If you're looking for removable drive bays for RAID arrays, you should not choose USB because of the lack of controller support.
The REV drive from Iomega shines through its sound overall concept, very small tapes, plenty of space and high performance. The volumes are unfortunately not exactly cheap, so if a lot are used this will have to be factored into the cost. On the positive side, REV can replace existing tape solutions without causing too much disruption, and is also interesting for long-term backups.
If the backup volumes are changed regularly by hand, we recommend High Rely from Highly Reliable Systems. The 19" storage system is also connected via USB and provides up to seven drives - one for every day of the week. If and when capacities are no longer sufficient, simply exchange hard drives. Instead of the rack mount module, the maker offers similar solutions in desktop and minitower cases. What's interesting about this product is the fact that the manufacturer relies on relatively simple components.
The ARAID M100 from Accordance is the only device in the test that comes complete with a RAID 1 implementation. It doesn't require any drivers and enables the use of 2.5" hard drives (models for 3.5" are also available.) These products make sense if saved data must be accessed frequently and quickly.