Hmmm, My understanding is the amps only have inputs, and either receive the balanced signal or don't. So the amps are "truly balanced". A source or pre-amp unit (like my cd player) may have phase splitting hardware or not at various stages and be "truly balanced" from input to output or not...most consumer audio products I've heard of convert the balanced signals to "unbalanced" signals internally anyway, leaving noise reduction in the line as the primary benefit sound wise, though there may be slight sound differences that some find more or less pleasing vs RCA's. Nice to have the option.

Do they sell speakers with XLR connections? That signal's getting unbalanced at some point in the path anyway.

Personally I've heard some dB gains with XLR, and otherwise mixed results for sound quality. Some high end manufacturers insist they sound worse, some say they sound better. It's such a cheap feature to add though, no harm if some people can benefit from it.

Are there any sub $2000 a/v receivers offering XLR yet?