Diesel prices tend to move with heating oil prices, so there is an increase in the winter months and a decrease in the summer months. Currently diesel is about 10 cents cheaper than premium near me. In the winter, diesel can be 30 or 40 cents more than premium.
Regardless of price, diesel makes a ton of sense in a truck, and I'm surprised more auto makers aren't putting them in SUVs. The torque by itself is worth it. The mpg is a bonus. And the diesel clatter is pretty bad ass IMO.