I agree with most of what has been said here. I have used the Classic 6(12' pair) for a few years now, very reasonably priced and works well with my simple setup. I could have easily gotten away with less, maybe the Classic 2.5, but bigger is better, right? Not really, just half teasing there.
I tried the Ply 3.4 in my system, and it too is a great cable for the money. If I had to say anything about differences that to me were audible, it would be maybe a slight more detail and very slight extended upper end. I do find my Classic 6 to be maybe a touch soft in the upper end, but very smooth.
Most of Supra's products I think are great value, not hifi foo. FWIW.
