Gregg, you may have forgotten but you asked this a couple of years ago and James responded:
As he points out the preference for using the XLR output is covered in the FAQs.
Of course with a Naim amplification system you either have to use RCA/RCA or use a converter cable. However with a converter you lose the advantage of CMRR noise rejection as although the result provides an electrical connection it is no longer balanced. As I said at the time such a cable is nevertheless preferable to adaptor plugs.
As just about everything in this hobby it is a case of fitting theory to the practical reality of what we actually have so compromises often need to be made.