Just looking at the costs it doesn't pay out to me. Looking on line I find that the diesel option is $5000. MPG is 24 HWY for the V6 gas 4X4 and 28 MPG HWY 4X4 for the diesel. If you drive 15,000miles a year the V6 GAS engine will use 625 gal of fuel at $3.25 = $2031 a year. 15,000 miles in the DIESEL will use 535.7 gal at $3.75 for a total of $2009 a year. That's only $22 a year in savings, and that not including the costs of urea, that will be at least $20, so using the # from the internet I don't see any real savings for the diesel. Now, add the extra $5000 for the diesel option, and the extra costs for maintenance of the diesel, its a lot of money just to be able to use a green hose at the station. These are just numbers from the internet, but I do think they will be close. I know we never got over 28 MPG in our liberty, and it was a smaller rig and just a 4 cyc, but it only had a 5 speed automatic compared to the new 8 speed. I am also using the price difference between gas and Diesel at this time which is right at .50 a gallon right. The price difference over the last year has been between .75 to .00. The V6 gas is 290 HP compared to the 240HP for the diesel, but the torque is where the Diesel really shines.
Again, this is just my opinion, but for diesel engines fuel economy to really shine the price for diesel HAS TO BE the same as the gas or the extra MPGs don't pay out. Of course, if you are going to be doing a lot of towing the diesel might look better.