The newer and more expensive BelCanto ref XXXm line (I use the 1000ms) also uses a supplemental power supply internally that is integrated with the stock Icepower module. That helps optimize bass performance I believe and accounts for much of the price difference with these compared to other more stock Icepower amps I believe.
This is the main reason I elected to pay a hefty premium for these specific Icepower amps compared to others that use stock Icepower modules only and cost way less.
However, I have heard others that use Wyred Icepower amps with stock Icepower power supplies report very good results also. I have never heard these or compared so I cannot say for sure, but in general those who have seem to report only subtle differences as best I can tell.