I just got it, so I haven't used it for long yet, but the construction feels high-quality and sturdy.
There is visible reinforcement at the joints where the twisted cable meets the hard connectors on both ends (6,3 mm and 3,5 mm). This should help prevent the common tearing —and eventual loss of contact— typical of these connectors due to constant bending over the years. I’m optimistic this will last a lifetime; only time will tell, of course.
I really like the design as well. By using an intermediate twisted cable between the two connectors, it reduces the distance the adapter protrudes from the device. Since monochannel 6,3 mm instrument cables can be heavier than people expect, this design significantly reduces the leverage and strain on the input jack.