I vote 5.0. That is what I would buy if I was in the market right now.

I know 3 people that bought eco boosts. Of the 3, 2 have already sold them (after 1 year) because they were disappointed in the gas millage and had repeated mechanical issues that put the trucks in the shop.

I have 1 friend with a 5.0 and he has nothing but good to say about the truck. It has 3.73's and seems to get going pretty good for a truck....