I guess it's all relative. "Good" can be construed in different ways. It can mean 'sufficient' or 'decent' or 'OK' as in 'good enough'. Or like many companies products where they have a good, better and best quality of the same item where 'good' denotes their bottom line. I would imagine standard romex would not require the purest copper whereas the better speaker cable uses ultra or hyper-pure, perfect-surface, or whatever terminology the manufacturer uses for extremely pure, continuous cast copper. And of course there is the dielectric and other insulation materials used. And then again I'm sure many feel there is no difference so you pretty much have to go on faith or try it yourself.
