We’ve successfully implemented the QNAP TS-439 Pro II at the primary site and have migrated all shared storage data for vSphere 5 to it.
As you can see, it is a very polished unit. There are four drive bays with key locks and a front USB port.
There are four SATA ports for 3.5″ hard drives.
Not many superfluous accessories included in the box. I purchased Cat6 cables for superior throughput.
The rear of the unit has four additional USB ports, two gigabit ethernet ports and two eSata ports. Currently, the two ethernet ports are bonded using LACP to the Cisco switch for increased throughput / failover / load balancing.