To me it would depend on the overall usage of the truck. I just went thru the same thing about a month and half ago. My 07 2500 5.7 was getting tired so I traded it in on a 17 2500 6.4 hemi. They had a 17 2500 with a cummings on the lot for 2K more (had less options). For how much I use my truck and for what I use it for, I just decided to go with the hemi, even though the cummings will hold its value WAY better. I have a 70 mile round trip to the racetack towing a 24' box trailer in the 7500-800 lb range. Three are 3 decent "hills" as we say here in Maryland that I have on my way. I only have about 600 miles on the truck thus far, but get 9 mpg towing and 14-16ish empty. Not that great, but towing is actually 2 mpg better than my old truck and empty is the same. New truck does have 4.10's which helps and it has alot more get up and go than my old 5.7 with 3.73s.