+100000 to this, verbatim.
I've had dunlops fail. The dunlop's ball-bearing system is basically locking using 1/64" or less of metal into a tiny groove, and that can totally wear away with time.
I can't really see how schallers can actually fail, besides the nut coming loose. Which, just like any other screw on your guitar or amp, make sure it's tightened regularly if you gig regularly. I hold the bottom with a wrench, and TORQUE that sh*t down TIGHT. Never had one loosen. If you're still afraid, use some loktite on the threads.