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.