They both have fine qualities that will work well in certain applications.
In my opinion, in my system, the Audioquest was a bit clearer with a tad more extension in the highs. The Acoustic Zen offered a slighter warmer sound with a fuller bass.
They both presented a pretty nice sound-stage, but the AZ stage was a bit deeper, which was more to my liking. Overall, I would give the slight nod to the AZ cables.