With EFIS systems, Make sure you find a certified installer. Do not use wood frame windows. In wall foan insulation should provide a vapor barrier, but use a vapor barrier paint on the inside to be sure.
Here in the Pacific NW there have been many problems with 8-10 yr old EFIS systems, exterior sheathing has rotted below the foam board, Wood window frames and door jambs have rotted out. As far as I'm concerned its great for business