Check the speed ratings for the stand-alone storage devices you are considering. The faster the storage devices are, the faster your backups will run.
Calculate the cost per gigabyte of storage by dividing the purchase price by the number of gigabytes. Compare this cost per gigabyte for each external hard drive or tape device you are considering.
Compare how difficult it is to use each type of stand-alone data storage. For instance, a tape drive or DVD burner array can be more cumbersome to use than an external hard drive array, since tape drives and DVD units require computer owners to swap out the media when it becomes full.
Check the encryption capabilities of each stand-alone storage option you are considering. If your home or office network contains personal or legally protected data, you will want to encrypt your data as it is backed up to the external storage devices. If this is a consideration, look for a stand-alone storage device that supports low-level encryption.