Musical Fidelity kw dm25 Transport & DAC

I noticed these advertised in the new Stereophile. The ad says the DAC can be run ss or tubes. Anyone heard these? What so they compare to?
I heard these at a local dealer. They were hooked up to a system using Thiel speakers. The sound was very good. I did not compare them to other dacs or cd players. I read a review of this combo and the reviewer could not detect any differences between tube and solid state outputs. I did not try this feature when I listened to them.
Where was the review? Were you listening through tubes or solid state (if you know)?