These foam houses really do not impress me so far. Especially if u need an ERV or even worse a dehumidifier. Seems u just need more equipment to deal with the tightness of the home. Then u got to maintain / repair this additional equipment.
If I built again dont think I would use foam. JMO
Here in the Atlanta area... I know a couple of spec builders.
They do the roof (under the roof) with foam, then use conventional insulation in the walls. The result seems to work out as a good compromise.