I extracted this from Cambridge Audio's Audiophiles Guide to Bit-Perfect USB Audio:
ASIO (Audio Stream Input/Output) is another method of audio transport which is superior to WASAPI as it bypasses the Windows Kernel Mixer (and the distortion this adds). Just like WASAPI, to use ASIO the media player will normally require some kind of output plug in, but it is only possible to use ASIO in Class 2 USB Audio mode (which allows transmission of higher data rates) using a dedicated driver (such as the free Cambridge Audio USB 2.0 driver). [Aune T1 can only support up to 24/96kHz so maybe doesn't require Class 2 USB Audio mode. Note: Class 2 USB Audio mode is NOT USB2.0.]
ASIO is preferable to all Kernel streaming audio transport methods (eg. WASAPI or DirectSound) as it delivers lower latency, better jitter and no mixing of audio streams.
Can anyone verify this?
+1 I've read ASIO will have less jitter than anything else, if implemented/supported properly. The problem that I read (and reason why I think a lot of people stick with WASAPI) is with the driver implementation with Windows, which ends up creating more jitter than exclusive mode WASAPI.