EB has only been for sale for about a month, so even the first owners don't have much time/miles/experience with them, like even filling the tank more than once. And it's winter in most of the country, not generally towing season yet.
Theoretically, the EB should have plenty of an advantage over the 5.4L. More torque at 1700rpm-5000rpm than the 5.4L has at its peak, let alone across the usable range. plus the lower power loss (not nothing, but smaller than naturally aspirated) at higher altitudes.