Is the volume control dithered? With my HRT Streamer II for example, Audirvana automatically removes the volume slider. Seems removal of the volume control and leaving it either to iTunes or the external DAC/AMP maybe the better option and in line with the minimalist UI approach.
Support for sound other than music would be great. What about support for non-iTunes streaming (browser, Pandora, etc.) audio? No one has figured that yet - PM has a plug-in but it is a real pain to use and doesn't seem to affect/improve SQ.