I have a 2014 FC25' and a 2007 Grand Cherokee CRD 3.0L Diesel. I have added the Green Diesel Engineering EcoTune Re-flash to take the torque to about 440 Ft-lb. I also use a Tekonsha Brake Controller and a 90-00-1000 Equalizer Hitch.
My experience so far (4000 miles) after towing thru West Virginia, Kentucky and the Skyline Drive in Virginia has been outstanding. I am getting 16 MPG and, if I want to, I can actually keep up the speed at 65 MPH in the hills with no signs of effort on the Diesel. The brakes and brake control seem to be doing well also with no signs of overheating or loss of control. The 5-speed Getrag automatic also allows me to engine-brake by manually downshifting downhill. The sway is also in check and the combination feels safe and controlled.
I chose the 2007 Grand Cherokee with the Mercedes-built 3.0 Liter CRD because its performance and ruggedness and so far I haven't been disappointed. The 4-wheel Quadratrac II is also a welcome bonus.
I know I sound like a commercial, but I am a happy camper!