Mac Rumors posted a news story that Barefeats has benchmarked the first 3rd party USB 3.0 interface for the Mac from CalDigit

"Wait a minute. Apple hardware and software does not support USB 3.0." Yes but CalDigit has developed OS X drivers for their PCIe and ExpressCard USB 3.0 host adapters.

  First 3rd Party Mac USB 3.0 Interface Benchmarked