The director class switches usually reside at the center of a SAN and offer up more ports and redundant parts than average switches. The systems can be used to link together SANs and to connect numerous devices from servers and storage boxes to tape libraries. While very high-end, a 528-port box should prove attractive to large customers, according to Cisco.
I'd definitely like to see a picture of this thing in action. Cisco is also working to not alienate those who have bought their smaller MDS devices, and is making the modules for the 9513 backwards compatible with others.