We are using STK 9840 drives.  The 9840 drives seem much more reliable than
the 3590.  We have had some problems with the reliability of the 9840 tapes.
When one fails, we have lost between 20 and 120 gigabytes of data.  One way
to work around the 9840 reliability is to dual copy most backups.

One disadvantage of the 9840 drives is that the service techs are not
allowed to perform many services on the drives.  If a drive malfunctions, it
must be pulled and replaced.  I do not know if this applies to the 3590
drives.  We have an excellent relationship with our STK service reps, and
they seem concerned about our business, not just meeting the terms of their
service contract.  IBM is not concerned about our business, and service
calls to IBM are often frustrating.

When we analyzed the two different high-capacity drives, the level of
service played a big part.

Doug James