I moved from Asus to GB for USB stability issue. I am not sure how much of that was chipset or the controller used, but have not experienced any instability with USB ports. I mapped everything out using USBMap.kext and using opencore 0.5.9. I do use Caldigit TS3+ TB dock and connect all my mission critical devices (Camera, capture card, Audio Interface, 4K monitor) so that I can easily swap between my MBP and Hackintosh with one cable. I will try connecting some of those devices to the Desginare port, to see if I can reproduce any instability. But, so far, the MB has been rock solid.