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 Gnu Swallow Tail Carver . 16 NS West . 15 NS Snowtrooper BIA
16 Burton Genesis X . 15 Now Drive
16 Flow Talon . 14 Flow Hylite