Hi there. I am interested in these products - the Boom as a standalone device or the Duet for use with an integrated amp and speakers.Can anyone explain to me why the Duet is more expensive than the Boom even though the latter has a built in amp and speakers. I can only assume it is because the Duet offers better audio quality via superior DAC etc but that wouldn't explain such a big price difference. What do users of each device think of the audio quality? Does using a subwoofer with the Boom make a big difference? Are there any stores where you can see/hear the Boom in action? Thanks.