Chris, all audiophile cable manufacturers will say they make the best sounding cable. Just ask them. You may also find that all loudspeaker manufacturers make the best loudspeakers, all DAC manufacturers make the best DAC s, all turntable manufacturers make the best turntable, all amplifier manufacturers the best amps etc. etc. Of course you could trust them 
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Also if you care to plough through that excessively long thread on ethernet cables you will find that a shielded cable ( single or double) is not the optimum choice for dCS equipment. It is a specific issue for dCS. Vovox’s double shielded ethernet cable might be advantageous in some unusual situations of abnormally high electrical noise but that is not likely to be of interest to us home users. So the Vovox statement "could "be right. But it is doubtful that the specific requirements of dCS equipment was accounted for ( unless referred to). So, putting aside my scepticism over manufacturers’ opinions on their own products, there really isn’t any real paradox to find in that statement.
Oh yes it is. I have posted on the subject several times, here is just one example: