All these share the same 2TB capacity and USB 2.0 connection available in the My Book Essential edition. However, they vary in port arrays and formatting. The Mac and Studio Edition both come pre-formatted in HFS+ for OS X systems, with the latter also offering FireWire 400/800 and eSATA interfaces in addition to a USB port. The Home Edition targets the widest possible audience with a Windows-friendly formatting, eSATA, FireWire 400 and USB interfaces and comes equipped with continuous backup software.
With the exception of the 2TB Mac Edition, which ships next month, all the drives should be available now at prices between $330 and $380 depending on the model.