Thanks! I find the main differences are due, first to capacitance, and second, to EMI/RFI rejection, elimination of handling noises, etc.
Cables with 25 pF/foot capacitance, like the Van Damme that PRS sells as premium cables, sound a little more accurate in the high frequencies than higher-capacitance cables, especially over longer runs. As an example, the Mogami cables run around 48 pF/foot, so runs under ten feet to the first buffered device work better for me with cables like the Mogami. I can run 25 feet of cable with the Van Damme with no noticeable signal loss.
I've been playing around with some recently-developed instrument cables by Sommer that have a 16 pF/foot capacitance, said to be the lowest capacitance instrument cable on the market. They sound great. The tradeoff is that they're a bit stiff compared to the Van Damme. At the level of the Sommer model I mentioned vs the Van Damme, the audible differences are very small, where they're clearer with the Van Damme vs Mogami.
There are players who want some high frequency rolloff in their cables. I've had some premium cables that sounded devoid of high frequencies (and unacceptable for me) that high-gain players have loved. The PRS sweet switch on the early models was a response to Carlos Santana's request to be able to make his guitar sound like it was connected to a very long cable (probably why I never use the sweet switch on my one guitar that has it).
You can tailor sound just that extra little bit with cable choices. And yeah, crappy cables don't sound very good at all for a variety of reasons.