It seems to me that cables invariably act as frequency tone controls with the specifc effects determine by inductance/resitance/capacitance.
If this is true, it would seem that there can be no best cable as it becomes almost totally system dependent.
I would think that given source A, pre-amp B, amp C, and speaker D we might be able to answer what is the "best" cabling for this particular system.
Beyond that, I think universal claims of which cabling is "best" are close to impossible.