i've had an silver Arctic Cable for quite some time now, so am comfortable with writing this post.
It is most definitely my favourite cable with the Utopia. i enjoy it the AC cable with the Utopia more than the Danacable Lazuli Reference and Moon Audio Black Dragon (both terminated for Utopia). i've also used ultrashort adaptors with cables from Norne (Silvergarde S3), JPS Labs (Superconductor) and PlusSound (X8 gold plated silver). The Utopia is such a fast and resolving headphone, but so far i found only the AC plays to that strength. I felt the other cables listed above (aside from the Black Dragon) seemed to dull out the upper registry, rounding off the top end just a bit too much.
There is this amazing clarity and transparency with the AC cable. the leading edge to notes is so clean, making vocals so crisp and clear. i also thought it was the most holographic with amazing 3d placement of elements in the music. it also had by far the best soundstage width, both laterally and in depth. Even with busy passages and songs with lots of instruments playing, there is really really good separation and just crazy pinpoint placing. In the lower registry, low end extension and texture were great, and there was fantastic punchiness and impact. The utopia is definitely not lacking in bass!
i've done countless quick a/b comparisons with this cable and my other cables and it really is no contest. not to say that the other cables are not good, just that they sounded better with other headphones. for eg, i preferred the JPS Superconductor with the Abyss 1266 (naturally) and the PlusSound X8 with the Verite Closed. The AC cable simply plays extremely well with the Utopia. Quite honestly, i'm done with a cable search for these headphones.
i have absolutely no complaints with the sound that i get with this cable. if i had any gripes, it would be with the construction; these are minor but i figure i might as well list them out. i would have preferred a heatshrink/sleeve over the furutech spring extension. the braids in the cable could have been tighter and more even. and lastly, the L and R markings on the headphone end are not lined up with the red dot on the utopia lemo connectors. the other cables i listed above all edge out the AC cable construction wise, but then again, it really is the sound that matters in the end.
if you have the Utopia, the AC cable is really really worth a try!