I own the Clearview Double Helix digital cable along with Cardas Lightning L-15 and Kimber Illuminations D60.
In comparison to the other two cables, the Double Helix doesn't seem to exagerate any freqs. They have good extension at both ends, but also very smooth. In my system they were the smoothest, but also the least dynamic. But, at almost one third the cost of the L-15 and D60 they are a very good bargain.
I should note that in my setup I have experienced a problem with them. I'm running mini monitors off of an integrated amp with a subwoofer. It seems that every time I turn the sub on and off a loud pop emanates from the speakers and a huge shift in sound quality accompanies it. It could be a ground issue, but I'm not sure. If you're not using a powered sub, you may not have the same problem.
I know of other Agon forum members that have had good results with the Double Helixes.