The current list of hard drive formatters that Digidesign does not have issues with are:

HDT ver 1.6.3
PowerTools ver 3.02
Anubis ver 2.5
Silverlining ver 5.6

Per Michael Aboud: It should be noted that there are no "real" issues by Digi against any formatting utility. As long as it formats it should technically be ok. The biggest issue was that you cannot format OR optimize (defrag) via the disk I/O card. The hard drive will need to be connected directly to Mac SCSI for BOTH of these utilities to function properly.