Stand Alone DAC Vs. Anthem Dacs

Does anyone know how the sound quality compares in a stand alone DAC like Benchmarks Dac1, or Bel Canto Dac2 compares to the sound you are going to get going straight to Anthem's D1?
What about using one of those DACs in conjunction with the D1? Would that be overkill, or too nominal to wory about? Would law of diminshing return apply in this case?
"too nominal to wory about"

I think that is your answer.

They maybe different but to say one is better would be difficult outside the context of your own personal tastes and system application.