Unless the ecoboost is getting jaw dropping increases in MPG over the v6, I would never take the turbo 4 cyl over a v6. Only reason to take the ecoboost is if you want the premium interior option cheaper and don't want to buy the premium GT.
The v6 and ecoboost models are a disappointment to me, GT is only one that isnt a total disappointment.
I agree, the 4 cylinder better have great gas mileage to make it worth it! I sure don't want to pay for the premium gas prices just for a turbo. At least my 2014 V6 is pretty close in performance with the newer 2015.