http://www.manualowl.com/m/Western%20Digital/WD3200H1U-00/Manual/131582 referance.
WD hard drive in an enclosure, It supports firewire, E-SATA, and USB.
When you say "micro USB to eSATA cable" usb and e-sata are not directally compatable, and any "cable" that would make them compatable would be an "adapter". The USB2 would always present the bandwidth limitation in any scenario where the USB is part of that chain of connections, and adapting doesnt always go very well. Therefore it would be no better than connecting up the USB itself, and way less problems.
Firewire would be quick, if you had one of those ports available.
The cable you show, is to break out a "Combo" port, do you have a sata+Usb combo port?