USB 3.0 hardisk dock: necessary investment

I didn't know why I hold off buying a few more USB 3.0 harddisk dock until this labor day weekend.  All I can say is that I really should have done it much earlier, since all my files are in my arrays of harddisk, and I need a better strategy to management and back up these Terabytes of data.

I used Microsoft SyncToy to synchronize 2 harddisk with 1.8 Terabytes of content.  With USB 3.0 harddisk dock, it took about 9 hours (9:00 am - 5:40 pm), which I found reasonable.