Trochilic's Skean vs Frostbringer offhand threat

[Jence]

Hey just looking to see if it's worth the purchase of a Frostbringer if one already has a Skean for offhand threat procs? I know the frosty has a better damage ratio, I suppose my question is more on the procs involved.

Skean has a Clockwork Poison proc, which is poison counters + an apparent stun as well? How would that factor in vs. the frosty ac debuff + dd proc?

Just looking for some feedback regarding these weapons for offhand in particular. Thanks for the insight!