I don't see USB 3.0 being a benefit on a wireless n network.
USB 3.0 is 4.8 gigabits per second or 572 MB/s and USB 2.0 is 480 Mb/s or 57 MB/s
But, gigabit ethernet is 1 gigabit per second or 120 MB/s.
And, fast ethernet is 100 megabits per second or 12 MB/s.
In my opinion USB 3 is only a slight improvement over USB 2 due to the network limitation until the network is capable of transfer speeds over 1 Gb/s (120MB/s) or you hook it up directly to your PC.
I tested transfers from PC to PC across my Gb network and I got 85 MB/s peak and 35 MB/s averages. From my network drive I got 10 MB/s peak and 5 MB/s average.
USB 2 is 480 Mb/s or 57 MB/s...my USB 2 drive, hooked to the WNDR, only transferred at 11 MB/s peak and 6 MB/s average. Nothing near the speed USB 2 should be transferring. Supposedly the WNDR has a USB 2 port, but is doesn't seem to transfer anywhere near USB 2 speeds. I can only assume usb 3 will return similar results.
If I had a choice...I would go with a really good network drive (ethernet capable, NOT USB) like the Netgear ReadyNAS NVX (RNDX4410) capable of 74 MB/s transfers over gigabit networks. Or build a server with SATA 2 or SATA 3 hard drives.
See NAS charts at http://www.smallnetbuilder.com/compo...nas/Itemid,190