There's a ton of info on the Ram 1500 Diesel site. I was considering the EcoD when I bought my 14 but after doing the math, it didn't make sense for me. I made this spreadsheet to compare both models and if you're buying it thinking you'll save money, you might be surprised.
The spreadsheet shows the cost for fuel (using $2 for gas and $2.50 for diesel), then you have DEF to worry about as well as $100 oil changes. Using these numbers and assuming the only price difference is the engine adder itself, it takes over 5 years to break even at 20k miles per year. What they also don't mention is that you lose a lot of the incentives with the EcoD, bringing the real price difference over $5k. When I was spec'ing my truck out to order, my net price difference was about $6k because of lost incentives.
Using today's fuel prices in Tulsa ($1.70 for gas and $2.49 for diesel), driving 15k per year, and assuming a $5120 adder over the Hemi, my payback would be 40 years! Now if you tow a lot, it might make more sense for the EcoD. Also, when fuel prices jump back up to where they were a few months ago, it will help a lot with the payback time line. There's also the coolness factor of the EcoD, might be enough to offset some of the extra money.
https://www.dropbox.com/s/bpd5soqbi6bdsum/Hemi-vs-EcoDiesel.xls?dl=0