I currently own both a Benchmark DAC 1 and a DacMagic. I use both in my main system. They're both very good (and the DacMagic is a very good value, to boot), but they sound quite different from each other.
The Benchmark is noticeably leaner sounding and, as with many components that are tonally balanced for this character, it is very revealing. The sense of transparency to the source is very high. From the upper mids through the treble (to the limit of my 51 year old hearing, anyway), the DAC 1 is "laid back" which provides a nice octave to octave balance. A bonus is superb imaging with dramatic depth.
The Cambridge is both warmer and a touch brighter. It might sound less "transparent", but more dynamic. Imaging is quite good, but not at the DAC 1 level.
To me, this is a system dependent choice. I rotate 4 different speakers (Merlin, Verity, Ohm+Velodyne, Magnepan+Velodyne) in my main system and each one sounds a bit different when a different DAC is rotated into service. The added dynamics of the Cambridge benefit both of the sub/sat combos, which are getting more time these days, so the DacMagic is my choice. OTOH, I prefer the Benchmark with the Verity and the Merlin is a toss-up.
All, of course, IMHO.
Hope that's useful.
Marty