Ecodiesel questions

I am in the market for a new truck and have been leaning towards an ecodiesel. But I know nothing about the engine, such as how many miles can the engine can hold up to, is the truck going to hold its value 5 years down the road, and just if its worth spending more money for the ecodiesel or if its better to just get a hemi. I am needing a truck reliable truck since I took a job away from home and am going to be putting a good amount of miles on the truck. any advise would be greatly appreciated