In the process of building my deck I learned that a lot of the fasteners aren't designed for use with the treated lumber beause the copper-based solution introduces a galvanic couple with the fasteners and accelerates their demise. Seems like a big oversight on the part of fastener manufacturers to not respond to this problem sooner.
Simpson Strong Tie recommends hot dipped galvanized fasteners yet right on the shelf at Lowes next to their decking connectors they are selling a box of mechanically galvanized structural screws. The mechanically galvanized fasteners are just tumbled in zinc and the adhesion isn't as strong.
In any case the zinc doesn't stand a chance against wet treated lumber. Simpson Strong Tie also recommends that you don't use stainless fasteners with their galvanized steel connectors because that creates a galvanic couple as well and can turn the connector into the anode.
So there isn't any real answer, though I would guess that the stainless screw + galvanized SST is a lesser evil than zinc plated screws in treated lumber. In the end I used Grip Rite epoxy coated screws (green) because they are supposedly rated for treated lumber in outdoor conditions.
Any experience anyone else can share?
A bit more on how I addressed some of those issues: