33/34mpg on a commute of 70 highway/30 stop and go city driving is not a problem if you drive like an adult. My drives, as you would expect, are full of grin inducing acceleration. I think I am hovering around 31mpg for commuting since the last reset a week ago, and that has a few WOT runs in 2nd gear to find out the top speed in 2nd, and some general hooniganism. On average, the ST gets the same or slightly better MPG than my 2011 Fiesta gets. The ST is around 31/33 MPG for my daily commute, my brother gets just under 30 since he has a lot more stop-n-go city driving, but has the same highway distance to cover as I do. Brandon will have the ST for next month and will be driving 80 miles on the highway for a round trip to his night classes. I am sure he will get some decent MPG numbers out of that run. I would get around 35MPG out of my 2011 Fiesta when I drove that route for a few years.
The best explanation I have ever heard concerning MPG and EcoBoost is that if you want V6 power, the I4 will deliver. If you want I4 MPG, it will do that too. It will not give you V6 power and I4 MPG at the same time. That is 100% correct. My wife drives her Escape 2.0L EcoBoost like she drove her 2.5L V6 Escape. The result is almost the exact same MPG. There is some driver input that is needed to get what you want out of the car. I prefer V8 power out of my I4 and am happy with less than steller MPG numbers.