AFAIK, SCSI is still the only hard drive interface that supports low
level
formatting. I can't tell you the number of IDE/EIDE hard drives I've had
to throw away over the years because power failures during write ops that
corrupt sector headers. Some later model EIDE drives can map those "bad"
spots away, but only SCSI allows you to repair that damage by laying down
new sectors, headers, gaps, etc.
Most SCSI drives can't do that either. The tools needed to do it are just
too complex to embed in the drive.
There are only two types of EIDE server drive users: those who have
s/EIDE server//
Disks fail. Reliability MTBF values vary by price of disk, but not because
of the interface. A 15000 rpm SATA2 drive with SCSI grade reliability is
going to cost SCSI like prices, but the controller is going to be a lot
cheaper, as are the cables