Those are absolutely BS. For each application their is a clear performance ceiling, and it's related to noise rejection. Any claims of "clearer highs" or anything like that are 100% BS, except I suppose you could have clearer highs compared to a noisy signal. The RCA's job is to transfer the signal it is given without allowing noise to enter. The only other issues aren't common except in complete garbage cables (very high resistance, very high capacitance, etc). Other features are purely related to build quality, cosmetics, etc.
Unbalanced: 100% shield coverage. This isn't really possible though, so the more the better. Usually 95-99% with a good shielded cable. Below that isn't too helpful because you just have a holey shield
Differential: A decent Twisted pair. Differential inputs compare the two signals it receives to remove most if not all noise from the line. This is obviously ideal, but most car audio amplifiers still do not use differential inputs.