I've only had the the toecaps slip once after 10 days on them, and I'm pretty sure it was my own fault from being careless and not putting them on properly. They work way better than I would've imagined, even on the smooth, rounded toebox of these NB x 686 boots.
16 NS West . 15 NS Snowtrooper BIA . 13 Salomon Pow Snake
15 Now Drive . 14 Burton Genesis
14 Flow Hylite