Hot swappable. Easy setup. eSATA and USB connection. Accepts 3.5" & 2.5" SATA drives.
Okay construction. Could be cheaper.
The best feature for this dock is the flexibility. Just plug in any HDD and connect to your computer or even an HD PVR. I have three of these things and never had any problems.
I just wish the HDD were more securely docked and less expensive.