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

@tvad .
I have to say my experience mimics yours. I had some XLR's from Ralph Karsten that I have been using for years, but went with some new AQ XLR cables ( I have found their new cables work extremely well with my systems).
And, to be honest, I do not find a significant difference in sound quality. Which leads me to concur with Ralph, that XLR cables are inherently immune from coloring sound reproduction. To be fair, my system isn't set up in the best configuration. When I get my new subs, I will have my dealer do his best to optimise with what I have, and if it results in better sound quality, I will post accordingly.
Bob

As long as source and the input are not ground related capacitance between wire and shield has no effect, but capacitance between wires still exists.  Dielectric with lower dielectric constant will reduce capacitance between wires.  Signal wires in XLR are usually twisted - a very effective way of reducing electrical noise pickup, but nothing is 100%.  Better cables often have better shields protecting better.

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.

I heard significant changes for the better when I switched from Mogami Gold XLRs to something else.