Apple did tweak the USB 3.0 drivers in 10.8.2 and even improved the native support for the Intel ports on the 7-series chipsets.
FL1100 is a four port USB 3.0 host controller with support for UASP (USB Attached SCSI Protocol) and it's xHCI 1.0 compliant, with the FL1009 being its two port equivalent. The NEC and ASMedia controllers don't support xHCI 1.0, but the Etron EJ168 controller used on many of Gigabyte's 6-series motherboards should be xHCI compliant.
This rules out xHCI 1.0 compliance as a potential driver limitation, so clearly Apple must've willingly added support for Fresco Logic's controllers. The good news here is that the two port FL1009 found on some Gigabyte models, like its X79 boards and the H61N-USB3 also works natively in OS X 10.8.2.
The performance is far below that which we've seen from every other USB 3.0 host controller in OS X so far and at least on the board we used to test the controller on, it would only work in one of the PCI Express x1 slots, as although it was seen by the OS in the secondary x16 slot, no USB devices attached to it would show up. On the upside, USB 2.0 devices works just fine with the FL1100, unlike what we've seen from the Intel USB 3.0 ports so far.