I got one of these:
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http://www.amazon.co.uk/Anker®-Uspe...UTF8&qid=1374688723&sr=8-1&keywords=anker+usb
And it's completely brilliant. VL812 chipset - so lightening fast - and it looks great and a perfect match for my iMac and Mac Mini. USB3 speed is just fast as if you directly connect devices to your Mac. And you can mix and match USB2 and USB3 devices at full speed as well. And it's rock solid. I run 7 or 8 devices on mine permanently and haven't had a solitary glitch out of it.
The only trouble is, it looks like Anker have perhaps discontinued it. I can't find it on the iAnker website, nor on Amazon.com. If you can find one, I strongly recommend it.