I could very well be wrong about this, but in my opinion, because the bandwidth a subwoofer cable needs to pass is so small (maybe 200Hz at the most, as opposed to a video cable which needs to pass several megahertz), a subwoofer cable may not need to be as "good" as other cables, of course, good construction and decent shielding shouldn't be overlooked.
My advice is; if the cable is visible, buy one that's good looking.