It needs to be pointed out that some components have balanced outputs but DO NOT have fully balanced circuitry. And in this case may actually degrade sound if XLRs are used. Components with fully balanced circuitry are more expensive, and the only way to know for sure if the component is fully balanced is to contact the manufacturer. That said, Sonic Frontiers strongly recommends using the balanced outputs of their fully balanced Line series of pre-amps and Power series amps. I have their Line 2 pre-amp but haven't tried XLRs yet, but intend to, as all my components are fully balanced. One reason (maybe?) to prefer XLR is that they provide a more positive connection, ie I have some high quality RCA ICs that are a little loose,-- and no way to tighten them. A Synergistic Research Tech. Rep. said he personally preferred RCA interconnects for its (perceived) slightly fuller, richer sound, BUT he also said that among his collegues he was probably out voted by those who preferred balanced. Like everything else in this weird hobby, you just have to try it and see which you prefer. That's what I intend to do. Cheers. Craig.