I just went from a 15 eco 3.55 to a 15 hemi 3.21. You can only get the 3.55 or 3.92 with the diesel. I LOVED the eco mpg, 24 average, 30 on hwys going 60ish. The low end torque was great, but it falls on its face after about 40mph. Passing power was lacking. Where I live diesel is consistently 20+cents more. DEF fluid wasnt too much of a concern, oil changes are more expensive as well.
The hemi im averaging about 18.5 on my route to work compared to the eco at 23-25. Power wise there is no comparisons, even with the 3.21, no 3.55 offered with the hemi.
Im happy with my choice, and the mainreason for switching was i just missed having some muscle. You really cant go wrong with either. I had ZERO issues with my 2 years and 20k miles with the ECO.
If quickness and acceleration is a big concern, stay with the hemi. If you can live without having quick power, and you can get a good deal, grab an eco! 80 miles a day, you would be benefiting from the mpgs more than I did.
Let me know if you have any questions!