My only complaint with my cheap (around £2 each) inductive sensors is that mine don't seem to have any significant separation between on and off points. Not generally a problem, except that if I home all three axes and then jog in X or Y, the vibration tends to trip the Z limit switch as the sensor is just at its trigger point. Difficult fix, though - jog the Z down a millimetre or so first. Repeatability seems to be spot on, at least for my woodworking purposes. Must be our cold northern climate that means they work better here?