Monster makes a wide array of cables, including some that are very high end. I initially purchased a pair of Monster Rock Instrument Cable - 21 Feet - Angled to Straight 1/4-Inch plug to use with my keyboards, but when it came time to purchase cables for my bass and guitar I thought I'd pinch a few pennies. I am so glad I did.
I compared this cable model to the more expensive models I previously purchased and, aside from looks, could not detect any difference in sound. I Swapped back and forth between my guitars and keyboards, ensuring that each model was used on each instrument - still no difference.
What the more expensive model has going for it is looks. I am not sure it (the higher priced model) is even more sturdy because the molded stress relief ends on this model seem to make it more reliable than its pricier sibling.
Bottom line: carefully compare both cables using your own instrument and amp - if possible - before making a purchase decision. You may find, as I did, that higher price does not necessarily equal higher value, even from the same manufacturer.