I am using the Perfect Wave DAC with a Macbook. I purchased from Underwood, where Walter gave me a generous trade on a Musical Fidelity A5 CDP (with Underwood Level 2 mods). I was using a Marsh 2000b, which I sold off and am now going preless into an Odyssey Dual Mono.
Although the trade made it impossible to do an A/B, the PW set up sounds very distinctly better than the A5. Deeper and more articulate bass, better detail, less limited "sweet spot," etc. A more natural sound overall.
Upgrading a stock USB cord to a Locus Design Polestar between MAC and DAC made a noticeable improvement.
I also changed the powercord on the DAC, an entry level PS Audio, to Chris Hoff's new BPT design.
I upgraded the interconnects, Gronneberg RCA, to BPT's new silver interconnect, balanced.
The BPT cables improved things noticeably as well: more detail, better low end, more lifelike -- highly recommended.
In short, I am very pleased indeed with the Perfect Wave DAC. If you are contemplating making the move to "computer audio" -- IMO, an excellent idea -- the Perfect Wave is worth considering.
John