The main difference I see between home and essential on that site is home is more expensive but supports more types of connectors to the computer (firewire and esata) - they're better than usb 2 if you're going to be copying large amounts of data at a time in one sitting e.g. video editing, but make sure your PC/laptop has the appropriate connectors as well though

esata is also much faster, but is currently the rarest of the three port types on computers. USB2 is sufficient for more general purpose and less heavy usage though.