I have owned the NAD T747 and although my current Bel Canto DAC and Amp combination was per-dated by some other components I can offer two opinions. First, the Bel Canto should blow away your current NAD as it did with mine with both Focal and Dynaudio Speakers. Second, I would highly recommend the newer Bel Canto C5i overe the older, less featured S300iuas I believe it to have a better amp section and a substantially better DAC.
Totem and Bel Canto?
Right now I have a NAD T747 and a pair of Rainmakers on Atacama stands and I would like to upgrade my sound. I am leaning towards either buy a NAD 275 power amp and running the speakers through that or a Bel Canto Integrated (either the S300iu or C5i). Anyone have experience with either of these? Not sure if it matters but I only have digital material(no cd or vinyl) so I was thinking that the Bel Canto might have the better DAC.