Harpoon vs shock lance?

[Gryndeon]

Met at least three bears today looking for ao3 harpoons. Specs wise it seems like the shock lance is better, and I don't understand why the harpoon would be so desirable (I have the pink and purple harpoons). Can anyone please explain?

[jonboy]

Break armor proc that stacks, lance break armor, does not stack.

[Gryndeon]

Ah. Okay, that makes sense. Thanks. :)