I found a couple of postings on the web that talk about the differences between the different storage technologies. Good read.
http://www.50mu.net/2013/03/27/scsi-ata-sas-nl-sas-and-sata-whats-the-difference-part1/
http://www.50mu.net/2013/04/02/scsi-ata-sas-nl-sas-and-sata-whats-the-difference-part2/