I suspect all or most of the other full sized vans get better mileage. For one, Nissan makes decent power in their motors but terrible mileage. My Frontier only gets about 17mpg for a mid sized truck with a V6. Second, the NV is like driving a brick. Look at its shape. The least aerodynamic vehicle on the road. But it has a large interior for a standard roof van, is comfortable, drives great, is reliable, and at least when I was buying, was a little less expensive than everyone else.