Zone 6 BC Canada

Curious of people’s experience with perfect walls or PERSIST WRBs. It looks like I can get a good deal on ice and water shield to do the roof and walls if preferred but is there an advantage to a vapour permeable WRB? 

inside to outside-
—1×6 t&g wood paneling and/or lath and clay plaster. 

-2×6 fir framing
-1/2” plywood sheathing
-WRB
-2 layers 2.75” reclaimed fibreglass faced Polyiso 
-1×4 vertical rainscreen 
-wood or metal siding.