The MD1400 is a JBOD and not part of the Dell storage line any more. It can be hooked up to a H830/840 which is a PERC for the PowerEdge Server. We use them as Backup Storage.
The Former MD3420 was a iSCSI,FC,SAS Storage which could expand by addings MD14[2|0]0 JBODs.
At the entry level Dell offers the Powervault ME or SC3020.
Regards,
Joerg