I always figured a cable was a cable. And electron goes in one end, and another pops out the other end. A single copper wire should theoretically sound totally fine, right? But it turns out it's not so simple. Klotz make cables with lower capacitance, so there's no loss of sound. What this is means is, more sparkle, clarity and air in the very highest frequencies. 

For electric guitar this wouldn't matter, and might even sound weird (which is why Klotz make cables tuned especially for electric guitar). But for acoustic guitar and vocals it's a revelation. Everything has more detail and sounds more real. The only bad part is the first time you try them, you get this sinking feeling that you've been missing all of this sound for years! Argh… 

Klotz cables not only have better signal transmission, but they make awesome quality road-tough cables, and they can make custom stuff too, which is great for me with two outputs on my guitar, one of which is stereo. 

Anyway, they're awesome. I use their lowest capacitance cables, which for guitar is the Titanium Supreme, and for vocal it's the M5 Supreme.