The EcoBoost was only designed for a 10 year 170k mile lifespan. That may be part of the reason they're not lasting 300k miles. They were never really intended to. Ford published this when the introduced them and then took down the paper in it. But you can still find all the old news about it.
Hard to argue with the performance - at least new. The car and driver long term test raptor lost something like 50+hp by the end of the first year when the retested it. It also lost significant time in the 0-60 and 1/4 mile tests. I hope that's not reflective of the general experience with them.
I rented a mustang a few months ago. After a week I was kinda thinking about buying one. So I guess I liked the little turbo 4. More so than the nx200t I had as a loaner. I'd take a well built turbo engine. Might even consider buying a tundra with the turbo if the mpg is good.