Bel Canto DAC 2 and Sonos

I have a Sonos ZP90 and was thinking of picking up a Bel Canto DAC 2 to use with it. They are selling routinely for $500 used on this site. Has anyone else used this combination?

If so, a few questions:
1) Do you think the sound is a noticeable improvement over the Sonos internal analog outs?
2) Does the Sonos' volume control as well as Line-In function perfectly fine using the Bel Canto DAC2 and the ZP90?

Thanks, and any listening impressions are welcome.