Is a balanced XLR cable inherently less critical than a single ended RCA one?

Mike, I used Mogamis between my Coincident CSL preamp and my M-60's.  I changed the room a bit and I needed a longer pair ~30 ft, and couldn't get what I wanted from Mogami.   I bought a pair of Signal Cable Silver XLRs at about 5 x the cost of the Mogamis I had previously used.   They made a nice difference, but my guess is that you would not get any benefit if you were going from an MP-3 to M-60's.  You might hear a difference going from your TT to your Mp-3, but you might not.  BTW, VH audio also makes some nice balanced cables, but they are a good bit more expensive.   If you don't need a long length to go from your TT to your preamp, it might be worth trying the Signal cable silvers.  If you don't hear a difference, you haven't lost much.

I have 25' runs of balanced interconnect between preamplifier and amplifier.  I tried three different pairs.  They all sound different.  One was best.  For me it was NOS Discovery Cable.

It all depends. When I upgraded my preamp to an ARC Ref 6 and my amp to an ARC 150SE, I tried five or six different XLR’s from Mogami up to Cardas Clear Beyond and they all sounded quite different. Morrow MA6 was the worst sounding, the Mogami was second worst, I can no longer recall what else I tried but there were several loaned to me at various price points and the Cardas sounded "right" immediately.
I never doubt Ralph Karsten’s technical knowledge or his statements about his own gear. But you can not paint broad swaths as to all gear. ARC warns their customer on the first page of the manuals to the above pieces to buy the very best balanced cable the customer can afford. After reading the views on this Board I bought the Mogami Golds and really wanted to believe that with balanced it would not matter. I had already spent my last discretionary dollar on the amp and preamp at the time. So there is no doubt in my mind that my impression is not due to ARC’s statement-I was biased in the opposite direction. So I will say it again-it all depends.
I am having a new bespoke built DAC assembled by Slawa Roshkow of SW1X that is true balanced, his DAC III Balanced. Dr. Roshkow says that despite being true balanced, he thinks. it sounds best run SE and that running balanced is only best for long runs. But-he says it still sounds far better than the non-balanced version of the same DAC because with this particular piece, the output transformers and related circuits resemble an amplifier and pass the output signal far better than using capacitors in place of the transformers (if I understand him correctly).

This guy lied balanced is always better there will be a bigger difference when you get some real cables.Have fun!!