The internal Superdisk 120MB floppy is connected through the IDE port. External Superdisk can either be USB or parallel port.
Internal Zip Drive are either SCSI or IDE. External Zip can be SCSI, USB or parallel port.
Avoid the parallel port drives in either case.
I have one IDE superdisk that replaces the floppy. The superdisk is a wonderful replacement, quiet, gentle and fast.
I have SCSI zip drives on both of my computers. It is fast and reliable. The zip drive has a much larger installed base. If you need to exchange data with someone, it is the way to go.