This weekend Wes (I-SIG) and I got together to compare the Bel Canto and Benchmark DAC's in my system. We ran The Bel Canto into "Aux1" on the preamp, and the Benchmark into "CD." This allowed us to A/B by remote, very cool. Both were used with the C.E.C. CD-3300 as transport. The coax out on the CEC was used for the Bel Canto, the AES/EBU out for the Benckmark. The Bel Canto does not have an XLR digital in. We got lucky as output levels were probably within .25dB of each other, the Bel Canto having just a touch more output.
Without droning on with all the usual audiophile terminology and 50 cent words....the 2 sounded 99.9% indentical. The only difference I could note was noticed during a track that had "hand clapping" (Incubus, "Are you in?"). The Bel Canto made the hand clapping sound just a touch (we're talking miniscule) higher in pitch. When I noticed this, I played the track for Wes several times and he noticed as well. Could it have been the slight output increase in the Bel Canto?---I don't think so, it was more of a "pitch" thing than a "level" thing. Other than that difference, I could hear nothing else in the 6 plus hours of listening we did.
The choice between these 2 is really about features. Niether has a power switch; the Benckmark has XLR ins/outs, the Bel Canto does not. The Benchmark has irratatingly bright LED's on the front, the Bel Canto (thankfully) does not. The Benchmark has a dual headphone output coupled to a very nice headphone amp; the Bel Canto does not. The Benchmark can be used as a standalone preamp, the Bel Canto cannot.
Just depends on what features are applicable to your personal wants. If you're looking for streamlined simplicity, go with the Bel Canto; if you're a headphone geek, need XLR, or want to use your DAC as your preamp, go for the Benchmark. I run the Benchmark in "dedicated" DAC mode.
Wes should chime in soon with his impressions...