Yes, I have heard the Au24 interconnects in 2 different systems. Overall, they are a nice cable. To me, they come across as being slightly laid back & have a slightly inferior transient response compared to my TARA Labs RSC Master Gen 2 interconnects.
To me, the Au24 & the TARA Labs RSC Master Gen 2 are the ying & the yang of cables. BETWEEN THESE 2 CABLES: the Au24 is laid back & seems to emphasize the music, glosses over some of the inner details & forgoes some of the transient attack. The TARA Labs RSC Master Gen 2 is more immediate, has better transient attack, better inner details & is truer to the recorded music. It is a more accurate cable of the two.
So, it depends on what your electronics are. Are they bright? Is your system very revealing as it stands now? If so, then you might want some balance i.e. the Au24. OTOH, if your system is already laid back/musical then the Au24 will take you deeper into that realm - may become excessive & artificial. In that case TARA cables are better.
BTW, my understanding is that XLO Signature cables are of the same flavour as the TARA cables & the Cardas cables are of the same flavour as the Au24.
Hope this helps. FWIW, YMMV, IMHO.