If you are referring to AR vs Monster, I think the build quality is worth the slight difference in price alone but Monster has various levels of quality as many cable manufacturers do.

If you are referring to cables in general, you must not miss a chance to try to stir up an argument. I have spent several hundred dollars on one cable and have been very satisfied with the noticed improvement. Cables can and do make a noticeable difference. If you haven't experienced it, too bad. It still doesn't change anything. And certainly I'm not suggesting anyone go buy cables on my word, there are plenty of ways to get cables for evaluation to see if one finds the difference worth the expense. Actually, cables can make such a difference I highly recommend trying before buying. I've done some extensive comparisons of various brands of cables and my conclusion is system synergy can sometimes trump the expense of the cable for best sound.