Looking at a 2013 Ram 2500 Hemi....input?

My friend who has pulled at least 20000 miles with me has a 2009 Ram 2500 with the Hemi. It does have the 4:10 rear end and 5 speed transmission. He pulls right at 8000 plus pounds 5th wheel. He never complains about fuel mileage, but I know it's in the 8-10 range, sometimes a little less depending on wind conditions. I pull about the same weight with a 2010 Cummins and he never has a problem keeping up with me in the hills. I am sure the Cummins shifts less, in more quiet in the hills and I do always spend less at the pumps when my fuel is more expensive, however I paid much more up front. I can use cruise control more than he wants to because his Hemi will down shift more to keep the set speed. With that being said I think you would have the 6 speed and I know that the 2010's and newer will ride much better, so there would be a plus. I do not know his empty mileage, but, again he does not complain and again he does have the 4:10. I do believe it's 17-18 in normal driving though.