Upsampling DACS: Take the Pepsi Challenge

HAs anyone used 2 of the following 3 relatively inexpensive upsampling DACs: Perpetual technologies, Bel Canto, MSB Link 3 with upsampling upgrade?? I am trying to sort out the details of the new technologies. The Perp Tech can "interpolate", while the others do not. I am under the impression that the "24 bit" part of this new technology has to do with s/n ratios aroung 140 db, which is great, but a little useless considering the other equipment in the system. The sampling freq is the part that has me all aflutter, because it seems to be getting closer to analog quality "infinite sampling" if you will... What do you think? Has anyone compared these dacs?? Thanks, gang.