Hi there!
I can't compare them since I never had SM, but I can tell you my observations on Bryn.
Yes It used to be bugged, which meant that your melee special abilities (Plague, Blood, Scourge Strike etc.) didn't have a chance to proc it, but It's working fine now. It's triggered quite a often, has no ICD and is around 5% of my damage in arenas, 10% if I get lucky. The rune is usually RotFC, but some people use Cinderglacier (It also increases the damage of your proc without consuming stacs).
I think SM has the edge because of the superior stats/weapon damage, however it's doesn't heal you or proc as often as Bryn's proc does. One thing is for sure tho, Bryntroll is a very strong weapon.
As for the Wrath sigil, I have no idea who designed such a trash piece of armor xD. Use Vengeful Heart for PvP.