It all depends on how you drive it, and what you do with it. My truck is my daily driver, it has the 3.5EB, and it tows very well, about on par with how my 99 7.3 did. It gets just under 18 MPG, my 14 3.5EB was in the 20 MPG range, but it was RWD with 3.15 gears.
The 2.7EB rates about 23 MPG real world, and is $4K lower than the Lion, and doesn't tow as well. Now if it does net real world 25 MPG, and you do a lot of driving like me, 33k a year and use Premium, which is now 30-50 cents a gallon more than diesel, the payout is much sooner. Now if you don't care about giddy up and towing of the 3.5EB, and just want a daily driver, the payoff is less than 1 year. The difference is roughly $2400 between the Diesel and the 3.5EB. Premium is $3.60 a gallon right now, Diesel $2.99, fuel used over 33K miles at 18 MPG is 1833 gallons, which comes out to $6599, while at 25 MPG, Diesel would use 1320 gallons, which comes out at $3946, a difference of $2653. Maintenance costs will be a little higher, it uses 6 quarts of oil, and the filters are more expensive, but will more than likely even out to what the 5.0 costs with full synthetic oil.
This is speculation in such that the engine does achieve the 25 MPG rating. If it gets higher then the payoff of course will be sooner. If it doesn't then it is a bust.
This of course mirrors the Hybrid premium vs regular car debates that have been ongoing for well over 10 years now, but you also have to remember that the premium is reflected in the resale as well, provided of course the engine does well.
While I would love the 25 MPG Diesel, I don't think I would be happy with the lower power and lack of towing, and would be much better off with a Superduty instead.
