We are using the ETI product....it seems to work well...Our only problem so
far is that it looks at the tmf backup as one object.  Regular volume
backups have a checkpoint option that periodically commits the backup to the
tsm database, the tmf backups cannot do this...
When we do the tmf backup it is quite large and runs for approx. 4-5 hours.
During this time frame the backup being one object puts a hold on the
recovery log and will not release until the backup completes and is
committed to the database.  During this 4-5 hour time frame if you
do any database intensive process your recovery log will fill up.  We got
around this by breaking up the one large tmf backup into numerous  smaller
backups which will not run as long.  We have increased our recovery log to
4.5 GB and we are still on occasion hitting the 80% max utilized
mark.  Be aware that the max for recovery log is just over 5GB and if your
server crashed due to recovery log being full, when you restart the server
you will need some extra work space in the log to get the server active.  If
you max out your recovery log and don't have any space to add for work a
database recovery will be required.... 

Robert Burton
Open System Storage Analyst
Royal Bank of Canada
315 Front St West
Toronto, On, M5V 3A4
416-348-3849
email: Robert.Burton AT royalbank DOT com