I previously had custom canals made for the standard earphones that came with my iPhone, and while a huge improvement in both sound and stability (keeping them in my ears while on the treadmill), they were still lacking in both sound and comfort.
Fast forward to my purchase of UM3X, and although I haven't even tried to experiment with the plethora of assorted earpieces designed to fit the ears more precisely, the comparison is staggering...
Incredible sound, even without custom canals, and comfort that greatly exceeds the hard plastic of the comfort canals I was using.
The noise reduction is comparable to what I've been used to with custom canals, even approaching that of my on the ear, noise reduction headphones from Bose.
Since the one thing that is likely to ever need repair is the cable, I opted to spend a few more bucks to get the ones with removable cables. Just switch them out for about $20 if needed and you're good to go.