Let the hive mind of Engadget get that for you.
"I finally got a new laptop with a lone USB 3.0 port. I'm now looking at getting a USB 3.0 hub with a power adapter so I can use both of my USB 3.0 hard drives at faster speeds. I've read lots of horror stories where some hubs either don't come with power adapters -- and as a consequence the portable drives don't work with them properly -- or they are designed poorly which results in USB 2.0 speeds. Or, the hard drives keep getting disconnected. Do your readers have any suggestions or experience using USB 3.0 hubs? Thanks!"
Couple gadget importers have been selling the X20 for a while. I'd just buy a 4gb X20 probably the best. I purchased the X20 from warehouse123 and it only costs $159 after the recent price drops. Best of all, recent price drops have made this all-around favorite surprisingly affordable. I highly recommend this device. It's well worth the price.