Depends on which SCSI format and which drive (7200/10,000/15k rpm) you are discussing...
http://en.wikipedia.org/wiki/SCSI#Traditional_SCSI_Parallel_Interface
Seek times don't remotely tell the whole story, as most modern mechnical 7200 rpm drives offer very similar performance, and most folks are more concerned with sustained throughput (influenced by individual drive's speed, how many drives are combined/striped in assorted RAID 1/5/6 arrays, potential bottlenecking by ancient PCI bus, SATA I/II/III specs, complexity of RAID controller, etc., etc..)
Typical 'seektimes' are measured in 4-8 millisec range....
For the desktop, SSD's have 'taken over', and SCSI is a rarely mentioned factor anymore.