Audiofun - the Async thing like any other marketing is carried too far, I agree. However, given that I have done 5 generations of USB interfaces (some Adaptive and some Async), more than any other manufacturer, I can guarantee you that you can NEVER achieve the same level of jitter with Adaptive that you can with Async, given the same designer and clock quality. This is simple physics. Free-running clocks will always be a better solution.
Async is a breakthrough technology for USB, there is no doubt.
Steve N.
Empirical Audio